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United States Patent |
5,270,072
|
Sato
,   et al.
|
December 14, 1993
|
Coating liquids for forming conductive coatings
Abstract
In accordance with the present invention, there are provided coating
liquids for forming conductive coatings, which comprise (i) a zirconium
oxysalt, (ii) a conductive substance and, if necessary, (iii) at least one
member selected from non-sedimentary silica dispersion and silicon
alkoxide or its derivative. The coating liquids, when coated on
substrates, form thereon transparent conductive coatings which are
excellent in transparency, scratch resistance, permanence properties and
adhesion to the substrates and, moreover, excellent in antistatic effect.
In particular, when the coating liquids for forming conductive coatings
mentioned above are coated by the spray method on appropriate substrates
followed by drying and/or heating, there are obtained face plates for
display devices, which have excellent regular reflection reducing effect
(non-glare) and antistatic effect.
Inventors:
|
Sato; Goro (Fukuoka, JP);
Komatsu; Michio (Tokyo, JP);
Hirai; Toshiharu (Fukuoka, JP);
Abe; Yoneji (Fukuoka, JP);
Mihara; Keiichi (Chiba, JP)
|
Assignee:
|
Catalysts & Chemicals Industries, Co. (Tokyo, JP);
Asahi Glass Company (Tokyo, JP)
|
Appl. No.:
|
746403 |
Filed:
|
August 16, 1991 |
Foreign Application Priority Data
| Feb 10, 1987[JP] | 62-27289 |
| Aug 25, 1987[JP] | 62-211096 |
Current U.S. Class: |
427/108; 427/110; 427/164; 427/165; 427/168 |
Intern'l Class: |
B05D 005/12 |
Field of Search: |
252/501.1,508,520
427/108,110,165,164,168,314,316
|
References Cited
U.S. Patent Documents
4563612 | Jan., 1986 | Deal et al. | 313/478.
|
4568578 | Feb., 1986 | Arfsten et al. | 427/45.
|
4783344 | Nov., 1988 | Bravet et al. | 427/316.
|
Primary Examiner: Lusignan; Michael
Attorney, Agent or Firm: Wenderoth, Lind & Ponack
Parent Case Text
This is a divisional application of parent application, Ser. No.
07/298,607, filed Oct. 11, 1988, now U.S. Pat. No. 5,078,915.
Claims
What is claimed is:
1. A method of processing a face plate for a display device, characterized
in that a face plate previously heated to and kept at
40.degree.-90.degree. C. is coated by a spray method with a coating liquid
for forming a conductive coating essentially consisting of a binder
substance and conductive substance dissolved or dispersed homogeneously in
a mixed solvent of water and an organic solvent wherein said binder
substance consists of a zirconium compound or a mixture thereof with other
inorganic compounds organometallic compound(s) and mixtures thereof,
followed by drying, firing or both drying and firing.
2. A method of processing a face plate for a display device, characterized
in that a face plate previously heated to and kept at
40.degree.-90.degree. C. is coated by a spray method with a coating liquid
for forming a conductive coating essentially consisting of a binder
substance and conductive substance dissolved or dispersed homogeneously in
a mixed solvent of water and an organic solvent wherein said binder
substance consists of a zirconium compound or a mixture thereof with other
inorganic compounds organometallic compound(s) and mixture there of,
followed by drying, firing or both drying and firing,
thereafter the resulting face plate is heated to and kept at
40.degree.-90.degree. C. and coated by the spray method with a coating
liquid comprising transparent protective components.
3. The method of processing a front panel for display device as claimed in
claim 2 wherein the coating liquid comprising transparent protective
component is homogeneous dispersion of silicon alkoxide in water, an acid
and an organic solvent.
4. The method of processing a face plate for a display device as claimed in
claim 1 or 2, wherein the conductive substance in the coating liquid for
forming a conductive coating is selected from the group consisting of tin
oxide, tin oxide doped with antimony, fluorine or phosphorus, indium
oxide, indium oxide doped with tin, or fluorine.
5. The method of processing a face plate for a display device as claimed in
claim 1 or 2, wherein the coating liquid for forming a conductive coating
further contains a stabilizer selected from the group consisting of
ethylene glycol, N-methyl-2-pyrrolidone, morpholine, ethyl cellosolve,
methyl cellosolve and N, N-dimethyl-formamide.
6. The method of processing a face plate for a display device as claimed in
claim 5, wherein the binder substance in the coating liquid for forming a
conductive coating consist of a zirconium oxysalt selected from the group
consisting of zirconium oxychloride, zirconium oxynitrate, zirconium
oxyacetate and zirconium oxyoxalate;
the weight ratio of the water to the zirconium oxysalt in terms of
ZrO.sub.2 is within the range of 0.1-40;
the weight ratio of the conductive substance in terms of oxide to zirconium
oxysalt in terms of ZrO.sub.2 is 1-5; and
the molar ratio of the stabilizer to the zirconium oxysalt in terms of
ZrO.sub.2 is 1-25.
7. The method of processing a face plate for a display device as claimed in
claim 5, wherein the binder substance in the coating liquid for forming a
conductive coating consists of a mixture of a zirconium compound with
other inorganic compounds organometallic compound(s) and mixtures there
of;
said zirconium compound being a zirconium oxysalt selected from the group
consisting of zirconium oxychloride, zirconium oxynitrate, zirconium
oxyacetate and zirconium oxyoxalate;
said other inorganic liquid and/or organometallic compound(s) being a
non-sedimentary silica capable of giving a sediment of less than 30% by
weight of the total amount of SiO.sub.2 when an aqueous dispersion
containing 2.0% by weight of said non-sedimentary silica in terms of
SiO.sub.2 is subjected to centrifugal sedimentation at 250,000 G for 1
hour;
the weight ratio of the water to the zirconium oxysalt in terms of
ZrO.sub.2 is within the range of 0.1-40;
the weight ratio of the conductive substance in terms of oxide to the sum
total of the zirconium oxysalt in terms of ZrO.sub.2 and SiO.sub.2 present
in the non-sedimentary silica is 1-5; and
the molar ratio of the stabilizer to the zirconium oxysalt in terms of
ZrO.sub.2 and SiO.sub.2 present in the non-sedimentary silica is 1-25.
8. The method of processing a face plate for display device as claimed in
claim 1 or 2, wherein the binder in the coating liquid for forming a
conductive coating consists of the mixture of a zirconium compound with
other inorganic compounds organometallic compound(s) and mixture thereof;
said zirconium compound is a zirconium oxysalt selected from the group
consisting of zirconium oxychloride, zirconium oxynitrate, zirconium
oxyacetate and zirconium oxyoxalate;
said other inorganic and/or organometallic compound(s) is a silicon
alkoxide compound represented by SiH.sub.a (OR).sub.b wherein a is an
integer of from 0 to 3, b is an integer of from 1 to 4 with the proviso
that a+b is 4, and R is alkyl having from 1 to 8 carbon atoms, or
(R'O).sub.a Si(OR).sub.b wherein a is an integer of from 1 to 3, b is an
integer of from 1 to 3 with the proviso that a+b is 4, and each of R and
R' is alkyl having from 1 to 8 carbon atoms, or R'.sub.a SI(OR).sub.b
wherein a is an integer of from 1 to 3, b is an integer of from 1 to 3
with the proviso that a+b is 4, and each of R and R' is alkyl having from
1 to 8 carbon atoms, and wherein a part of H in said silicon alkoxide
compound may be substituted by Cl or vinyl, or a condensate of up to 5
molecules of such a silicon alkoxide compound;
the weight ratio of the water to the zirconium oxysalt in terms of
ZrO.sub.2 falls within the range of 0.1-40;
the weight ratio of the conductive substance in terms of oxide to the sum
total of the zirconium oxysalt in terms of ZrO.sub.2 and silicone alkoxide
in terms of SO.sub.2 is 0.5-5.0; and
the molar ratio of the zirconium oxysalt in terms of ZrO.sub.2 to the
silicone alkoxide in terms of SO.sub.2 is 0.05-2.0.
9. The method of processing a face plate for a display device as claimed in
claim 5, wherein the binder substance in the coating liquid for forming a
conductive coating consists of the mixture of a zirconium compound with
other inorganic compounds organometallic compound(s) and mixtures thereof;
said zirconium compound is a zirconium oxysalt selected from the group
consisting of zirconium oxychloride, zirconium oxynitrate, zirconium
oxyacetate and zirconium oxyoxalate;
said other inorganic and/or organometallic compound(s) consists of a
non-sedimentary silica capable of giving a sediment of less than 30% by
weight of the total amount of SiO.sub.2 when an aqueous dispersion
containing 2.0% by weight of said non-sedimentary silica in terms of
SiO.sub.2 is subjected to centrifugal sedimentation at 250,000 G for 1
hour; and
a silicon alkoxide compound represented by SiH.sub.a (OR).sub.b wherein a
is an integer of from 0 to 3, b is an integer of from 1 to 4 with the
proviso that a+b is 4, and R is alkyl having from 1 to 8 carbon atoms, or
(R'O).sub.a SI(OR).sub.b wherein a is an integer of from 1 to 3, b is an
integer of from 1 to 3 with the proviso that a+b is 4, and each of R and
R' is alkyl having from 1 to 8 carbon atoms, or R'.sub.a (Si(OR).sub.b
wherein a is an integer of from 1 to 3, b is an integer of from 1 to 3
with the proviso that a+b is 4, and each of R and R' is alkyl having from
1 to 8 carbon atoms, and wherein a part of H in said silicon alkoxide
compound may be substituted by Cl or vinyl, or a condensate of up to 5
molecules of such a silicon alkoxide compound;
the molar ratio of the zirconium oxysalt in terms of ZrO.sub.2 to the sum
total of the non-sedimentary silica and silicon alkoxide in terms of
SiO.sub.2 is in the range of 0.05 to 2.0;
the weight ratio of the conductive substance in terms of oxide to the sum
total of the zirconium oxysalt in terms of ZrO.sub.2, non-sedimentary
silica and silicon alkoxide in terms of SiO.sub.2 is in the range of
0.5-5; and
the molar ratio of the stabilizer to the zirconium oxysalt in terms of
ZrO.sub.2 and SiO.sub.2 present in the non-sedimentary silica is 1-25.
10. The method of processing a face plate for a display device as claimed
in claim 1 or 2, wherein the binder substance in the coating liquid for
forming a conductive coating consists of the mixture of a zirconium
compound with other inorganic and/or organometallic compound(s);
said zirconium compound is dialkoxy-bisacetylacetonato zirconium in which
the alkoxy groups from 1 to 8 carbon atoms,
said other inorganic and/or organometallic compound(s) a partial
hydrolysate of a silicon alkoxide compound represented by SiH.sub.a
(OR).sub.b wherein a is an integer of from 0 to 3, b is an integer of from
1 to 4 with the proviso that a+b is 4, and R is alkyl having from 1 to 8
carbon atoms, or (R'O).sub.a Si(OR).sub.b wherein a is an integer of from
1 to 3, b is an integer of from 1 to 3 with the proviso that a+b is 4, and
each of R and R' is alkyl having from 1 to 8 carbon atoms, or R'.sub.a
Si(OR).sub.b wherein a is an integer of from 1 to 3, b is an integer of
from 1 to 3 with the proviso that a+b is 4, and each of R and R' is alkyl
having from 1 to 8 carbon atoms, and wherein a part of H in said silicon
alkoxide compound may be substituted by Cl or vinyl;
the weight ratio of the dialkoxy-bisacetylacetonato zirconium in terms of
ZrO.sub.2 to the silicone alkoxide in terms of SO.sub.2 is in the range of
0.05-1; and
the weight ratio of the conductive substance in terms of oxide to the sum
total of the dialkoxy-bisacetylacetonato zirconium in terms of ZrO.sub.2
and silicone alkoxide in terms of SO.sub.2 is in the range of 0.5-5.
11. The method of processing a face plate according to claim 2 in which the
transparent protective components-containing coating liquid is the same as
the coating liquid for forming the conductive coating with the proviso
that the conductive substance has been excluded therefrom.
12. The method of processing a face plate according to claim 2 in which the
transparent protective components-containing coating liquid which
essentially consists of a silicon alkoxide dissolved or dispersed
homogenously in a mixed solvent of water and an organic solvent wherein
the silicon alkoxide is represented by SiH.sub.a (OR).sub.b in which a is
an integer of from 0 to 3, b is an integer of from 1 to 4 with the proviso
that a+b is 4, and R is alkyl having from 1 to 8 carbon atoms, or
(R'O).sub.a Si(OR).sub.b wherein a is an integer of from 1 to 3, b is an
integer of from 1 to 3 with the proviso that a+b is 4, and each of R and
R' is alkyl having from 1 to 8 carbon atoms, or R'.sub.a Si(OR).sub.b
wherein a is an integer of from 1 to 3, b is an integer of from 1 to 3
with the proviso that a+b is 4, and each of R and R' is alkyl having from
1 to 8 carbon atoms, and wherein a part of H is said silicon alkoxide may
be substituted by Cl or vinyl, or a condensate of up to 5 molecules of
such a silicon alkoxide.
13. The method of processing a face plate according to claim 12 in which
the transparent protective components-containing coating liquid further
comprises diacetylacetonato-dialkoxy zirconium having alkoxy groups of
from 1 to 8 carbon atoms and a silicon alkoxide.
14. The method of processing a face plate according to claim 13, wherein
the weight ratio of the diacetylacetonato-dialkoxy zirconium in terms of
ZrO.sub.2 to the silicon alkoxide in terms of SO.sub.2 is in the range of
0.05-1.
15. The method of processing a face plate according to claim 2 in which the
transparent protective components-containing coating liquid consists
essentially of a binder substance dissolved or dispersed homogeneously in
a mixed solvent of water and an organic solvent, wherein said binder
substance is selected from the group consisting of a zirconium oxysalt
selected from the group consisting of zirconium oxychloride, zirconium
oxynitrate, zirconium oxyacetate and zirconium oxyoxalate.
16. The method of processing a face plate according to claim 2 in which the
transparent protective components-containing coating liquid consists
essentially of a binder substance and a stabilizer dissolved or dispersed
homogeneously in a mixed solvent of water and an organic solvent wherein
said binder substance consists of a mixture of a zirconium compound with
other inorganic compounds organometallic compound(s) and mixtures thereof;
said zirconium compound being a zirconium oxysalt selected from the group
consisting of zirconium oxychloride, zirconium oxynitrate, zirconium
oxyacetate and zirconium oxyoxalate;
said other inorganic liquid and/or organometallic compound(s) being a
non-sedimentary silica capable of giving a sediment of less than 30% by
weight of the total amount of SiO.sub.2 when an aqueous dispersion
containing 2.0% by weight of said non-sedimentary silica in terms of
SiO.sub.2 is subjected to centrifugal sedimentation at 250,000 G for 1
hour;
the weight ratio of the water to the zirconium oxysalt in terms of
ZrO.sub.2 is within the range of 0.1-40; and
the molar ratio of the stabilizer to the zirconium oxysalt in terms of
ZrO.sub.2 and SiO.sub.2 present in the non-sedimentary silica is 1-25; and
wherein said stabilizer is selected from the group consisting of ethylene
glycol, N-methyl-2-pyrrolidone, morpholine, ethyl cellosolve, methyl
cellosolve and N, N-dimethyl-formamide.
17. The method of processing a face plate according to claim 2 in which the
transparent protective components-containing the coating liquid is
dissolved or dispersed homogeneously in a mixed solvent of water and an
organic solvent, wherein said binder substance comprised of a zirconium
compound and a silicon alkoxide compound in which
said zirconium compound is a zirconium oxysalt selected from the group
consisting of zirconium oxychloride, zirconium oxynitrate, zirconium
oxyacetate and zirconium oxyoxalate;
said silicon alkoxide is a compound represented by SiH.sub.a (OR).sub.b
wherein a is an integer of from 0 to 3, b is an integer of from 1 to 4
with the proviso that a+b is 4, and R is alkyl having from 1 to 8 carbon
atoms, or (R'O).sub.a Si(OR).sub.b wherein a is an integer of from 1 to 3,
b is an integer of from 1 to 3 with the proviso that a+b is 4, and each of
R and R' is alkyl having from 1 to 8 carbon atoms, or R'.sub.a
SI(OR).sub.b wherein a is an integer of from 1 to 3, b is an integer of
from 1 to 3 with the proviso that a+b is 4, and each of R and R' is alkyl
having from 1 to 8 carbon atoms, and wherein a part of H is said silicon
alkoxide compound may be substituted by Cl or vinyl, or a condensate of up
to 5 molecules of such a silicon alkoxide compound;
the weight ratio of the water to the zirconium oxysalt in terms of
ZrO.sub.2 falls within the range of 0.1-40;
the molar ratio of the zirconium oxysalt in terms of ZrO.sub.2 to the
silicone alkoxide in terms of SO.sub.2 is 0.05-2.0.
18. The method of processing a face plate according to claim 2 in which the
transparent protective components-containing coating liquid is a binder
substance and a stabilizer dissolved or dispersed homogeneously in a mixed
solvent of water and an organic substance, said binder consisting
essentially of a zirconium compound, a non-sedimentary silica and a
similar alkoxide compound wherein
said zirconium compound is a zirconium oxysalt selected from the group
consisting of zirconium oxychloride, zirconium oxynitrate, zirconium
oxyacetate and zirconium oxyoxalate;
said non-sedimentary silica is one capable of giving a sediment of less
than 30% by weight of the total amount of SiO.sub.2 when an aqueous
dispersion containing 2.0% by weight of said non-sedimentary silica in
terms of SiO.sub.2 is subjected to centrifugal sedimentation at 250,000 G
for 1 hour; and
said silicon alkoxide compound is one represented by SiH.sub.a (OR).sub.b
wherein a is an integer of from 0 to 3, b is an integer of from 1 to 4
with the proviso that a+b is 4, and R is alkyl having from 1 to 8 carbon
atoms, or (R'O).sub.a SI(OR).sub.b wherein a is an integer of from 1 to 3,
b is an integer of from 1 to 3 with the proviso that a+b is 4, and each of
R and R' is alkyl having from 1 to 8 carbon atoms, or R'.sub.a
(Si(OR).sub.b wherein a is an integer of from 1 to 3, b is an integer of
from 1 to 3 with the proviso that a+b is 4, and each of R and R' is alkyl
having from 1 to 8 carbon atoms, and wherein a part of H in said silicon
alkoxide compound may be substituted by Cl or vinyl, or a condensate of up
to 5 molecules of such a silicon alkoxide compound;
the molar ratio of the zirconium oxysalt in terms of ZrO.sub.2 to the sum
total of the non-sedimentary silica and silicon alkoxide in terms of
SiO.sub.2 is in the range of 0.05 to 2.0;
the molar ratio of the stabilizer to the zirconium oxysalt in terms of
ZrO.sub.2 and SiO.sub.2 present in the non-sedimentary silica is 1-25; and
wherein the stabilizer is selected from the group consisting of ethylene
glycol, N-methyl-2-pyrrolidone, morpholine, ethyl cellosolve, methyl
cellosolve and N, N-dimethyl-formamide.
19. The method of processing a face plate according to claim 2 in which the
transparent protective components-containing coating liquid is a binder
substance dissolved or dispersed homogeneously in a mixed solvent of water
and an organic substance said binder consisting essentially of a zirconium
compound and a partial hydrolysate of a silicon alkoxide compound wherein
said zirconium compound is dialkoxy-bisacetylacetonato zirconium in which
the alkoxy groups from 1 to 8 carbon atoms,
said partial hydrolysate of a silicon alkoxide compound is represented by
SiH.sub.a (OR).sub.b wherein a is an integer of from 0 to 3, b is an
integer of from 1 to 4 with the proviso that a+b is 4, and R is alkyl
having from 1 to 8 carbon atoms, or (R'O).sub.a Si(OR).sub.b wherein a is
an integer of from 1 to 3, b is an integer of from 1 to 3 with the proviso
that a+b is 4, and each of R and R' is alkyl having from 1 to 8 carbon
atoms, or R'.sub.a Si(OR).sub.b wherein a is an integer of from 1 to 3, b
is an integer of from 1 to 3 with the proviso that a+b is 4, and each of R
and R' is alkyl having from 1 to 8 carbon atoms, and wherein a part of H
in said silicon alkoxide compound may be substituted by Cl or vinyl; and
the weight ratio of the dialkoxy-bisacetylacetonato zirconium in terms of
ZrO.sub.2 to the silicone alkoxide in terms of SO.sub.2 is in the range of
0.05-1.
Description
FIELD OF THE INVENTION
This invention relates to coating liquids for forming conductive coatings
and more particularly to coating liquids capable of forming on substrates
such as glass, plastics, etc. transparent conductive coatings excellent in
scratch resistance as well as in adhesion to the substrates.
In other aspects, the invention relates to glass or plastic substrates
provided on the surface thereof with transparent conductive coatings
formed by using the above-mentioned coating liquids, and particularly to
display devices having front panels provided on the surface thereof with
said transparent conductive coatings.
BACKGROUND OF THE INVENTION
Since glass or plastics which are used as transparent substrates of varied
types including face-plates for Cathode ray tube (CRT), liquid crystal
display (LCD), etc. are insulating materials, the surface thereof is
liable to static electrification and hence the substrate surface tends to
attract dusts or the like. Furthermore, in electrodisplay devices such as
LCD, etc., miss-performance is sometimes caused by the presence of static
electricity. For solving such problems as referred to above, attempts have
often been made to prevent such substrates as glass, plastics, etc. from
their being electrostatically charged by virtue of imparting electrical
conductivity to the surface thereof.
In order to impart electrical conductivity to substrates, metallic thin
films or conductive inorganic oxide coatings are deposited on the surface
of substrate by the vapor phase method such as CVD method, PVD method and
vapor deposition method, etc. In an attempt to impart electrical
conductivity to the substrate surface by the vapor phase method, however,
there are such problems that vacuum deposition apparatuses are required
therefor, and that a surface area or shape of the substrate on which a
desired coating is formed is restricted by the size of said apparatuses to
be employed.
In light of the above problems, a process for imparting electrical
conductivity to substrates has been proposed, which process comprises
coating the substrate on the surface thereof with conductive coating
materials obtained by dispersing conductive substances in binder resins.
Where an attempt was made to form conductive coatings on substrates by
using conductive coating materials obtained by dispersing conductive
substances in binder resins such as acrylic resins, butyral resins, vinyl
chloride/vinyl acetate copolymer resins, etc., however, there were such
serious problems that the conductive coatings formed thereby are found
poor in transparency, scratch resistance, solvent resistance or in
adhesion to the substrates, though said conductive coatings are excellent
sufficiently in electrical conductivity.
Under such circumstances, there has earnestly been desired an advent of
coating liquids for forming conductive coatings which are excellent in
scratch resistance, solvent resistance and in adhesion to substrates as
well as transparency.
Apart from the purpose of forming conductive coatings on substrates,
however, Japanese Patent L-O-P Publn. No. 100943/1982 discloses silicon
oxide coatings containing 1-30 mol % of zirconium oxide with the view of
protecting the substrate surface and inhibiting reflection therefrom. In
this publication, it is stated that in the zirconium oxide-silicon oxide
coatings there are used, as the zirconium compounds, zirconium chloride
such as ZrCl.sub.2, ZrCl.sub.3 or ZrCl.sub.4 ; zirconium nitrate such as
Zr(NO.sub.3).sub.4 5H.sub.2 O; zirconium alkoxides and zirconium
diketonates.
However, when an attempt is made to form the zirconium oxide-silicon oxide
coatings by using coating liquids containing zirconium chloride, zirconium
nitrate, zirconium alkoxide or zirconium diketonate and silicon alkoxide,
it has been found by the present inventors that there is such a serious
problem that because of instability in water of zirconium chloride and
zirconium nitrate, the coating liquids containing the same cannot be
preserved over a long period of time and have a short potlife. Moreover,
even if zirconium oxide-silicon oxide coatings were formed by the use of
the above-mentioned coating liquids containing zirconium chloride and the
like, it was still necessary to heat the resultant coatings at a
temperature of at least 450.degree. C. Moreover, the coating liquids as
described above involved such a problem that said coating liquids must be
adjusted to pH 2-6 by a fresh addition thereto of a mineral acid such as
hydrochloric acid at the time when silicon alkoxides contained therein is
hydrolyzed.
On one hand, face-plates of display devices are required in some cases to
have a specular reflection reducing effect (hereinafter called non-glare)
in order to inhibit glaring of said face-plates, in addition to their
antistatic effect. In order to impart non-glare and antistatic effect to
face-plates of display devices, a process designed for the purpose
intended is disclosed, for example, in Japanese Patent L-O-P Publn. No.
16452/1986, wherein the face-plate composed of glass or plastics is
previously heated, and a colloidal solution of silicon compound such as
partially hydrolyzed silicic acid ester, a solution of reactive silicon
compound such as silicon tetrachloride, or a solution prepared by mixing
the above-mentioned solution with a water-soluble compound of inorganic
metal such as platinum, gold, palladium, tin or the like is sprayed over
said face-plate to form thereon a finely irregular coating, followed by
drying and heating.
Further, a process for forming a coating layer on a face-plate of Braun
tube is also disclosed, for example, in Japanese Utility Model L-O-P
Publn. No. 168951/1984, wherein tin oxide or indium oxide and silicon
oxide are mixed or laminated by the vacuum deposition or dip method to
form the coating layer on the face-plate.
In face-plate of display devices processed by the above-mentioned
processes, however, non-glare attained was found insufficient, antistatic
effect expected varied depending on ambient temperature and humidity, and
under certain circumstances resolving power of the display devices came to
decrease by the presence of the coating formed on the face-plate thereon.
Further, the finely irregular coatings as formed were weak in adhesion to
the face-plate and easily peeled off therefrom, were liable to scratching
as being low in mechanical strength, and tended to peel off or elute as
being lacking in permanence properties such as acid resistance, alkali
resistance, resistance to saline solutions and to water, thus no non-glare
and antistatic effect as expected could be maintained over a long period
of time.
The present invention is intended to solve such problems associated with
the prior art as mentioned above, and an object of the invention is to
provide coating liquids for forming conductive coatings, said coating
liquids being capable of forming on substrates such as glass, plastics,
etc. the conductive coatings excellent in scratch resistance, permanence
properties and adhesion to the substrates as well as in transparency and,
at the same time, which are capable of being preserved with excellent
stability over a long period of time.
A further object of the present invention is to provide glass or plastic
substrates provided with transparent conductive coatings formed by the use
of such coating liquids as mentioned above, said conductive coatings being
excellent in transparency, scratch resistance, permanence properties,
adhesion to the substrates and antistatic effect, or glass or plastic
substrates provided likewise with transparent conductive coatings having
non-glare in addition to the above-mentioned functions. Another object of
the present invention is to provide display devices having face-plates
provided with transparent conductive coatings having the above-mentioned
functions.
DISCLOSURE OF THE INVENTION
The first coating liquid for forming conductive coating of the present
invention is characterized in that a zirconium oxysalt and a conductive
substance are homogeneously dissolved or dispersed in a mixed solvent
comprising water, an inorganic solvent and a stabilizer.
The second coating liquid for forming conductive coating of the present
invention is characterized in that a zirconium oxysalt, a non-sedimentary
silica and a conductive substance are homogeneously dissolved or dispersed
in a mixed solvent comprising water, an organic solvent and a stabilizer.
The third coating liquid for forming conductive coating of the present
invention is characterized in that a zirconium oxysalt, silicon alkoxide
or its derivative and a conductive substance are homogeneously dissolved
or dispersed in a mixed solvent comprising water and an organic solvent.
The fourth coating liquid for forming conductive coating of the present
invention is characterized in that a zirconium oxysalt, silicon alkoxide
or its derivative, a non-sedimentary silica and a conductive substance are
homogeneously dissolved or dispersed in a mixed solvent comprising water,
an organic solvent and a stabilizer.
The fifth coating liquid for forming conductive coating of the present
invention is characterized in that diakoxybisacetylacetonato zirconium, a
partial hydrolysate of silicon alkoxide and a conductive substance are
homogeneously dissolved or dispersed in a mixed solvent comprising water
and an organic solvent.
The substrates of the present invention, on which transparent conductive
coatings have been formed, are characterized by having a total light
transmission of at least 80%, a haze of less than 10%, a surface
resistivity of from 10.sup.3 to 10.sup.11 .OMEGA./, and a glossiness of
less than 190% as measured at an angle of 60.degree. in accordance with
the glossiness measuring method stipulated in JIS K 7105-81.
The display device of the present invention, in which a transparent
conductive coating has been formed on the surface of a face-plate, is
characterized in that the transparent conductive coating is composed of
zirconium oxide, silicon oxide and a conductive substance, and the
face-plate, on the surface of which said transparent conductive coating
has been formed, has a glossiness of 30-100% as measured at an angle of
60.degree. in accordance with the glossiness measuring method stipulated
in JIS K 7105-81, a resolving power of at least 50 bars/cm, and a surface
resistivity of 10.sup.3 -10.sup.11 .OMEGA./.quadrature..
The first process for manufacturing the display device of the present
invention is characterized in that any one of the above-mentioned second
to fifth coating liquids for forming conductive coatings of the present
invention is coated by the spray method on a face-plate of said display
device previously heated to and maintained at 40.degree.-90.degree. C.,
followed by drying and/or heating.
The second process for manufacturing the display device of the present
invention is characterized in that any one of the above-mentioned coating
liquids for forming conductive coatings is coated likewise on a face-plate
of said display device, dried and/or heated, and a coating liquid
containing a transparent protective component is coated by the spray
method on the face-plate heated to and maintained at 40.degree.-90.degree.
C., followed by drying and/or heating.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are schematic views for measuring a resolving power (bar/cm)
of the display device of the present invention.
BEST MODE FOR PRACTICE OF THE INVENTION
First, the coating liquids for forming conductive coatings of the present
invention are illustrated below in the concrete.
The first coating liquid for forming conductive coating of the present
invention comprises a homogeneous solution or dispersion of a zirconium
oxysalt and a conductive substance in a mixed solvent comprising water, an
inorganic solvent and a stabilizer. The components homogeneously dissolved
or dispersed in the mixed solvent are illustrated hereinafter.
Useful as the zirconium oxysalts are zirconium oxychloride, zirconium
oxynitrate, zirconium oxyacetate, zirconium oxyoxalate and the like. Of
those exemplified above, particularly preferred are zirconium oxychloride
and zirconium oxynitrate. Such zirconium oxysalts dissolve in water and
organic solvents such as alcohols and the resulting solution is made acid
when water is present therein.
The conductive substances used in the present invention are those which are
known hitherto such as tin oxide, tin oxide doped with antimony, fluorine,
phosphorus or the like, indium oxide or indium oxide doped with tin. These
conductive substances are preferably in the form of fine particle having
an average particle diameter of less than 0.4 .mu.m.
In the application of the present first coating liquid to a face-plate of
display devices such as CRT, LCD and the like or to a platen glass for
copying machines or the like where a high transparency with a low haze is
required, it is preferable to use in said coating liquid the conductive
substances having an average particle diameter of 0.01-0.1 .mu.m. Even
though an average particle diameter of the conductive substance contained
in the coating liquid is less than 0.1 .mu.m, however, the substrate to
which said coating liquid has been applied will decrease in transparency
if the major proportion of particles of said conductive substance has a
particle diameter exceeding 0.1 m and, therefore, it is preferable that at
least 60% of the total of the particles is occupied by those having an
average particle diameter of less than 0.1 .mu.m.
In the present invention, it is particularly preferable to use as the
conductive substances the products which are obtained on the basis of the
process disclosed in a publication titled "Process for preparing
conductive fine particles" (Japanese Patent Appln. No. 51008/1987) or a
publication titled "Tin oxide sol and process for preparation thereof"
(Japanese Patent Appln. No. 75283/1986), both filed by the present
applicant. That is, preferably useful as the first conductive substances
of the above-mentioned products are conductive metallic oxide fine
particles which are obtained by the above-cited process, wherein an
aqueous solution of a tin or indium compound is maintained under the
condition of pH 8-12, the compound in the solution is gradually hydrolyzed
to form a sol containing colloidal particles, and the resulting sol is
dried and calcined followed by pulverization.
The starting materials used in the above process are tin or indium
compounds which are water soluble and capable of hydrolysis in the pH
range of 8-12, and usable are in the concrete such tin compounds as
potassium stannate, sodium stannate and the like, or such indium compounds
as indium nitrate, indium sulfate and the like.
When a metallic element present in an aqueous solution of a tin or indium
compound (hereinafter sometimes called the starting solution) is either
one of tin or indium, the resulting fine particles are composed of tin
oxide or indium oxide. In that case, however, conductive fine particles
doped with a foreign element can be obtained by dissolving small amounts
of a compound containing said foreign element in the starting solution.
For instance, conductive fine particles composed of tin oxide doped with
antimony or fluorine can be obtained by dissolving small amounts of tartar
emetic (antimonyl potassium tartarate) or ammonium fluoride in the
starting solution containing a tin compound, and conductive fine particles
composed of indium oxide doped with tin can be obtained by dissolving
small amounts of a tin compound in the starting solution containing an
indium compound.
Conductive particles doped with foreign elements may also be prepared by
the following processes. That is, conductive fine particles composed of a
tin compound doped with antimony, phosphorus, fluorine and the like can be
prepared by a process which comprises using an aqueous solution of a tin
compound as the starting solution, gradually hydrolyzing the tin compound
in the solution under the aforementioned pH condition to form a sol,
recovering colloidal particles from the resulting sol, impregnating the
recovered colloidal particles with an aqueous solution of at least one of
an antimony compound, phosphorus compound and fluorine compound, and
thereafter drying the thus impregnated colloidal particles, followed by
calcining. Furthermore, conductive fine particles composed of an indium
compound doped with tin and/or fluorine can be prepared by a process which
comprises using an aqueous solution of an indium compound as the starting
solution, forming a sol in the same manner as above, recovering colloidal
particles from the thus formed sol, impregnating the recovered colloidal
particles with an aqueous solution of a tin compound and/or a fluorine
compound, and then drying the thus pregnated particles, followed by
calcining. In cases where the starting solution, even of an aqueous
solution of a tin compound or an indium compound, is used, when by-product
salts are formed during the source of forming a sol, not only colloidal
particles formed in the sol tend to agglomerate but also a specific
resistivity of the conductive fine particles obtained becomes higher by
virtue of admixture with the by-product salts formed. It is therefore
recommended that where formation of by-product salts is expected, the
by-products salts as formed are washed to remove from colloidal particles
recovered from the sol formed by hydrolysis, prior to impregnation of the
colloidal particles with an aqueous solution of the foreign element
compound.
Generally speaking, a concentration of the tin or indium compound contained
in the starting solution is preferably in the range of 5-30% by weight,
though the concentration may be selected optionally.
Usually, the reaction temperature of the hydrolysis may be selected at
choice in the range of temperature between 30.degree. and 90.degree. C.
After preparation of the sol colloidal particles formed therein are
recovered by filtration therefrom, and the colloidal particles recovered
are rinsed to remove by-product salts and the like attached to said
particles, dried, calcined and then pulverized to obtain conductive fine
particles. The fine particles thus obtained are sintered to a certain
extent during the calcining step and an average particle diameter of the
particles becomes about 20-50 .mu.m but the particles are easily released
from their sintered state when subjected to the subsequent pulverizing
step, and the fine particles are then processed by an ordinary
pulverization means to give conductive fine particles answering the
objects of the present invention, which have an average particle diameter
of less than about 0.4 .mu.m when they are incorporated into coating
materials. The fine particles obtained in the manner now described are
found to contain only small amounts of coarse particles, for example,
those having a particle diameter of larger than 0.8 .mu.m.
Pulverization of the conductive substances may be carried out before or
after mixing thereof with other components such as zirconium oxysalts and
the like. The conductive substances can be pulverized by conventionally
known methods, for example, those utilizing an attritor, sand mill, ball
mill, triple roll or the like devices.
The conductive substances thus obtained may be used, when they are
particles, as they are, or they can also be used after dispersing them in
water or organic solvents.
The second conductive substance preferably used in the present invention is
a conductive tin oxide sol obtained by heat treatment of fine particles of
tin oxide or tin oxide doped with foreign elements in aqueous acid or
alkali solutions.
The fine particles of tin oxide or tin oxide doped with foreign elements
used herein may be those obtained by the first process mentioned
previously, or those obtained by conventionally known methods.
This conductive tin oxide sol may be obtained by heat treatment of the
above-mentioned fine particles of tin oxides in aqueous solutions of acids
such as mineral acids or organic acids or aqueous solutions of alkalis
such as alkali metal hydroxides or quaternary ammonium salts. The heating
temperature employed in this case is preferably less than about
200.degree. C. Suitable amounts of the acids or alkalis used in the
aqueous solutions is at least 5% by weight based on the fine particles to
be treated. An average particle diameter of particles dispersed in the
conductive tin oxide sol thus obtained is less than 0.1 .mu.m, and more
than 60% of the total particles is occupied by particles having an average
particle diameter of less than 0.1 .mu.m.
The above-mentioned conductive tin oxide sol is usually an aqueous sol, but
it may also be used as an organic sol, if necessary, in which a part or
whole of water has been replaced by an organic solvent such as alcohol or
the like.
Organic solvents used in the coating liquids for forming conductive
coatings of the present invention are alcohol such as methanol, ethanol,
n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, etc., esters such
as methyl acetate, ethyl acetate, etc., ethers such as diethyl ether,
etc., ketones such as methyl ethyl ketone, etc., ethylene glycol
monomethyl ether and the like, which are used either singly or in
combination.
The stabilizers used in the present coating liquids, either singly or in
combination, are ethylene glycol, N-methyl-2-pyrrolidone, morpholine,
ethyl cellosolve, methyl cellosolve, N,N-dimethylformamide, etc.
In the first coating liquid for forming conductive coating of the present
invention which contains the above-mentioned components, the molar ratio
of the stabilizer to the zirconium oxysalt in terms of ZrO
(stabilizer/ZrO.sub.2) is 1-25, preferably 2-25. If a value of this ratio
is less than 1, gellation of the coating liquid for forming conductive
coating these components tends to occur undesirably and, on one hand, when
this value exceeds 25, the coating liquid inhomogeneously cures when it is
coated on a substrate to cure, whereby the conductive coating formed
undesirably poor in permanence properties.
Further, the weight of water present in the coating liquid is preferably
less than 40% of the whole weight of said coating liquid with the
condition that the weight ratio of the water to the zirconium oxysalt in
terms of ZrO.sub.2 (water/ZrO.sub.2) satisfactorily falls within the range
of 0.1-40. If the above-mentioned ratio of water/ZrO.sub.2 is less than
0.1, gellation of the zirconium oxysalt occur undesirably and, on one
hand, when said ratio exceeds 40, the addition effect of the stabilizer
disappears, with the result that adhesion of the coating liquid for
forming conductive coating to a substrate becomes poor undesirably.
Furthermore, the weight of the water exceeds 40% of the whole weight of
the coating liquid, the addition effect of the stabilizer disappears
likewise, with the result that adhesion of the coating liquid for forming
conductive coating to a substrate becomes poor undesirably.
The sum total of the conductive substance and zirconium oxysalt in terms of
ZrO.sub.2 is preferably 0.1-10% by weight based on the whole weight of the
coating liquid for forming conductive coating. It is not economical to use
these two components in an amount of less than 0.1% by weight and, on one
hand, if said amount exceeds 10% by weight, gellation of the coating
liquid for forming conductive coating tends to occur undesirably and no
possibility of the long-term preservation of said coating liquid can be
expected.
Still further, the weight ratio of the conductive substance to zirconium
oxysalt in terms of ZrO.sub.2 (conductive substance/ZrO.sub.2) is
preferably 1-5. If this value is less than 1, the resulting conductive
coating becomes poor in electrical conductivity and, on one hand, when the
value exceeds 5, adhesion between a substrate and the conductive coating
formed thereon undesirably decreases.
The coating liquids for forming conductive coatings as illustrated above
may be prepared by mixing an aqueous solution of a zirconium oxysalt with
a conductive substance and a stabilizer and, if necessary, removing part
of the water present in the mixture therefrom by distillation or
ultrafiltration, and thereafter adding an organic solvent to the mixture,
followed by homogeneous mixing.
The second coating liquid for forming conductive coating of the present
invention is illustrated hereinafter.
This coating liquid for forming conductive coating comprises a homogeneous
solution or dispersion of a zirconium oxysalt, non-sedimentary silica and
conductive substance in a mixed solvent comprising water, organic solvent
and stabilizer. The zirconium oxysalt, conductive substance, water,
organic solvent and stabilizer used in the coating liquid are the same as
those used in the first coating liquid for forming conductive coating of
the present invention as illustrated above, and hence herein illustrated
is the non-sedimentary silica.
The non-sedimentary silica used in the present invention is intended to
designate that when an aqueous dispersion containing 2.0% by weight of the
non-sedimentary silica in terms of SiO.sub.2 is subjected for 1 hour at
250,000 G to centrifugal sedimentation, the sediment left thereby is less
than 30% by weight of the total amount of SiO.sub.2. An aqueous dispersion
of a non-sedimentary silica is obtained by removing a great part of alkali
from an aqueous solution of alkali silicate, for example, by replacement
of the alkali with hydrogen in the aqueous solution of alkali silicate by
means of ion exchange, dialysis or the like. The stabilizer is used in the
non-sedimentary silica dispersion in an amount of at least 0.5 mole based
on 1 mole of the non-sedimentary silica.
Such a stabilizer mentioned above plays a role in the stabilization of
non-sedimentary silica in the dispersion by inhibiting gellation of said
silica.
In this non-sedimentary silica, it is desirable that the amount of residual
alkali represented by the SiO.sub.2 /M.sub.2 O ratio (in which M
represents an alkali metal) is at least 200, preferably at least 1000.
Such non-sedimentary silica as referred to above is illustrated in detail
in Japanese Patent Appln. No. 187835/1986 filed previously by the present
applicant.
In the second coating liquid for forming conductive coating of the present
invention which contains the components as mentioned above, the molar
ratio (stabilizer/ZrO.sub.2 +SiO.sub.2) of the number of moles of the
stabilizer to the number of the sum total of moles of the zirconium
oxysalt in terms of ZrO.sub.2 and of SiO.sub.2 present in the
non-sedimentary silica is 1-25, preferably 2-25. If this value is less
than 1, gellation of the coating liquid tends to occur and a pot life
(useful life) of said coating liquid becomes short and, on one hand, when
said value exceeds 25, the coating liquid does not cure homogeneously when
it is coated on a substrate, with the result that the conductive coating
formed becomes poor in permanence properties.
In this second coating liquid, the amount of water present is preferably
less than 50% by weight based on the weight of the coating liquid with the
condition that the weight ratio (water/ZrO.sub.2) of the water to
zirconium oxysalt in terms of ZrO.sub.2 is 0.1-40. If the water/ZrO.sub.2
weight ratio mentioned above is less than 0.1, the zirconium oxysalt
undesirably tends to gel and, on one hand, if said weight ratio exceeds
40, the addition effect of the stabilizer disappears and the coating
liquid undesirably becomes poor in adhesion to a substrate. Furthermore,
if the amount of water used exceeds 50% by weight of the coating liquid,
the addition effect of the stabilizer disappears likewise and the coating
liquid undesirably becomes poor in adhesion to a substrate.
The sum total of the conductive substance, SiO.sub.2 present in the
non-sedimentary silica and the zirconium oxysalt in terms of ZrO.sub.2 is
0.1-20%, preferably 0.1-10% by weight of the coating liquid. If a value of
the said sum total is less than 0.1% by weight, the use of such coating
liquid is not economical and, on one hand, if said value exceeds 20% by
weight, undesirably the coating liquid tends to gel and cannot be
preserved for a long period of time.
The weight ratio (conductive substance/ZrO.sub.2 +SiO.sub.2) of the
conductive substance to the sum total of the zirconium oxysalt in terms of
ZrO.sub.2 and SiO.sub.2 contained in the non-sedimentary silica is
preferably 1-5. If a value of this weight ratio is less than 1, the
resulting coating becomes poor in electrical conductivity or does not
become porous and, if this value exceeds 5, the resulting coating becomes
poor in adhesion to a substrate. The weight ratio (SiO.sub.2 /ZrO.sub.2)
of SiO.sub.2 contained in the non-sedimentary silica to the zirconium
oxysalt in terms of ZrO.sub.2 is preferably 0.05-1. If a value of this
weight ratio is less than 0.05, adhesion of the conductive coating to the
substrate undesirably tends to become poor. Whereas, if this value exceeds
1, the conductive coating tends to become less durable.
The coating liquid for forming conductive coating as illustrated above may
be prepared by mixing together an aqueous solution of the zirconium
oxysalt, the conductive substance and a dispersion of the non-sedimentary
silica and, if necessary, removing a part of water therefrom by
distillation or ultrafiltration, followed by homogeneously mixing the
resulting mixture with an organic solvent.
The third coating liquid for forming conductive coating of the present
invention is illustrated hereinafter.
This coating liquid for forming conductive coating comprises a homogeneous
solution or dispersion of a zirconium oxysalt, silicon alkoxide or its
derivative and a conductive substance in a mixed solvent comprising water
and an organic solvent. The zirconium oxysalt, conductive substance, water
and organic solvent used in the coating liquid are the same as those used
in the first coating liquid for forming conductive coating of the present
invention, and hence herein illustrated is the silicon alkoxide or its
derivative used in this coating liquid.
The silicon alkoxide or its derivative used in the present invention
includes compounds or condensates (up to pentamers) having 1-4 alkoxy
groups of 1 to 8 carbon atoms, said compounds being represented by
SiH.sub.a (OR).sub.b (a=0-3, b=1-4, a+b=4, and R is alkyl), (R'O).sub.a
Si(OR).sub.b or R'.sub.a Si(OR).sub.b (a=1-3, b=1-3, a+b=4, and R and R'
are each alkyl), or derivatives of the compounds or condensates
represented by the above-mentioned formulas in which a part of H has been
substituted with Cl, vinyl or the like group. Of those mentioned above,
preferred are mixture of one or two or more compounds represented by the
formula Si(OR).sub.4 (wherein R is CH.sub.3, C.sub.2 H.sub.5, n--and
iso--C.sub.3 H.sub.7, or n--, iso--, sec--and tert--C.sub.4 H.sub.8).
In the third coating liquid for forming conductive coating of the present
invention, which contains the components as mentioned above, the zirconium
oxysalt and silicon alkoxide or its derivative are used in such an amount
so that ZrO.sub.2 /SiO.sub.2 (molar ratio) of the zirconium oxysalt in
terms of oxide to silicon alkoxide or its derivative in terms of oxide is
in the range of 0.05-2.0, preferably 0.2-1.0. If a value of this ZrO.sub.2
/SiO.sub.2 (molar ratio) is less than 0.05, the resulting coating
undesirably becomes poor in permanence properties and, on one hand, if
this value exceeds 2.0, the resulting coating undesirably decreases in
adhesion to a substrate and optical characteristics (haze, total light
transmittance).
The presence of water in the coating liquid is necessary for hydrolysis
reaction of silicon alkoxide. It is preferable to decide the amount of
water in the coating liquid according to the amount of the silicon
alkoxide or its derivative in the mixture, and desirably the water is
contained in the coating liquid in such an amount so that the H.sub.2
O/SiO.sub.2 molar ratio in the mixture of the water to silicon alkoxide or
its derivative in terms of SiO.sub.2 is at least 2. If a value of this
ratio is less than 2, no coating is obtained since undecomposed silicon
alkoxide or its derivative remains, as it is, even after formation of the
coating.
The content of the conductive substance, when expressed as MOx in terms of
oxide, is preferably in such an amount so that MO.sub.x /(SiO.sub.2
+ZrO.sub.2) (weight ratio) is 0.5-5.0. If a value of this weight ratio is
less than 0.5, undesirably the resulting conductive coating becomes
excessively low in electrical conductivity and, on one hand, if this value
exceeds 5.0, undesirably the resulting conductive coating becomes poor in
adhesion to a substrate.
When the solids content (conductive substance+ZrO.sub.2 +SiO.sub.2) in the
conductive coating liquid is less than about 20% by weight, a coating
answering the objects of the present invention is obtained. However, if
this solids concentration exceeds 20% by weight, the coating liquid
becomes poor in stability and cannot be fit for a long-term preservation.
If this solids concentration is excessively low, such an inconvenience
that the coating operation of the conductive coating liquid must be
repeated several times to obtain a desired coating is experienced and
hence a practically useful solids concentration is at least about 0.1% by
weight.
Since water and an organic solvent such as alcohol or the like are present
in this conductive coating liquid as mentioned above, the zirconium
oxysalt dissolves in the water and organic solvent, whereby the coating
liquid comes to exhibit acidic properties with a pH of less than 2. On
that account, there is no need of incorporating into the coating liquid an
acid catalyst such as hydrochloric acid, nitric acid or the like with the
purpose of hydrolyzing the silicon alkoxide or its derivative.
The fourth coating liquid for forming conductive coating of the present
invention is illustrated hereinafter.
This coating liquid for forming conductive coating contains a
non-sedimentary silica and a stabilizer in addition to such components as
used in the above-mentioned third coating liquid for forming conductive
coating. The non-sedimentary silica and stabilizer used in this coating
liquid are the same as those used in the second coating liquid for forming
conductive coating of the present invention.
When this non-sedimentary silica is used together with the silicon alkoxide
or its derivative in the coating liquid for forming conductive coating,
total light transmittance of the resulting conductive coating is increased
and transparency of said coating is improved and, moreover, permanence
properties of the coating is not marred.
The non-sedimentary silica is preferably used in such an amount so that the
weight ratio (SiO.sub.2 in non-sedimentary silica/SiO.sub.2 in silicon
alkoxide or its derivative) of SiO.sub.2 in the non-sedimentary silica to
the silicon alkoxide or its derivative in terms of SiO.sub.2 is less than
9. If a value of this weight ratio exceeds 9, such a new problem that the
heating temperature of the resulting coating must be increased to about
300.degree. C. or higher in order to improve permanence properties of the
coating arises undesirably, though transparency of the coating is further
improved.
Even in the case where the non-sedimentary silica is used, the operation
conditions and compositions to be employed therein, such as the ratio of
ZrO.sub.2 to total SiO.sub.2 in the coating liquid and the like, are the
same as those employed in the aforementioned case where only the silicon
alkoxide or its derivative is used.
Illustrated below are the processes by which the above-mentioned third and
fourth coating liquids for forming conductive coatings of the present
invention are prepared.
The zirconium oxysalt, silicon alkoxide or its derivative and conductive
substance, if necessary, the non-sedimentary silica and stabilizer, are
homogeneously mixed together in a mixture of water and an organic solvent.
In that case, the order of dissolving or dispersing these components is
not particularly limited, for instance, an aqueous solution of the
zirconium oxysalt may be mixed with an organic solvent such as alcohol or
the like, and the resulting mixture may be incorporated with an alcohol
solution of the silicon alkoxide or its derivative, or these solutions
mentioned above may be mixed together at a stroke. It is also possible to
increase stability of the dispersed particles of the components by
incorporating the coating liquid with a surfactant at the time when the
above-mentioned solutions are mixed together.
The fifth coating liquid for forming conductive coating of the present
invention is illustrated hereinafter.
The fifth coating liquid for forming conductive coating of the present
invention a homogeneous solution or dispersion of
dialkoxybisacetylacetonato zirconium, a partial hydrolsate of silicon
alkoxide and a conductive substance in a mixed solvent comprising water
and an organic solvent. The conductive substance, water and organic
solvent used in this coating liquid, however, are the same as those used
in the aforementioned first coating liquid for forming conductive coating
of the present invention, and hence herein illustrated are the
diacetylacetonato-dialkoxy zirconium and partial hydrolysate of silicon
alkoxide.
The dialkoxy-bisacetylacetonato zirconium may be sufficiently useful if its
alkoxy group, preferably butoxy group, has 1 to 8 carbon atoms. This
dialkoxy-bisacetylacetonatozino zirconium plays a role in improving
dispersibility and heat stability of the conductive substance, and this
role is considered ascribable to the fact that the
dialkoxy-bisacetylacetonato zirconium acts as a protective colloid on the
conductive substance.
The partial hydrolysate of silicon alkoxide or its derivative used in this
coating liquid may be obtained by partial hydrolysis of the silicon
alkoxide or its derivative used in the third coating liquid for forming
conductive coating of the present invention.
As the conditions under which the partial hydrolysis is carried out, there
may be adopted a procedure generally employed for partial hydrolysis of
silicon alkoxide or its derivative. For instance, such conditions may be
adopted, wherein silicon alkoxide or its derivative is mixed with methanol
or ethanol, and the mixture is incorporated with water and an acid to
effect the partial hydrolysis of the silicon alkoxide or its derivative.
However, the partial hydrolysis conditions particularly preferred are such
that the acid used is preferably hydrochloric acid, nitric acid,
phosphoric acid or acetic acid, and the mixing ratio of the acid to
silicon alkoxide or its derivative (acid/SiO.sub.2) is preferably 0.01-0.5
(the weight ratio of the acid to silicon alkoxide or its derivative in
terms of SiO.sub.2). If a value of this ratio is less than 0.01, large
amounts of unreacted silicon alkoxide remain to exist in the mixture,
which undesirably mars electrical conductivity of the resulting coating
and, on one hand, if this value exceeds 0.5, the rate of the partial
hydrolysis becomes excessively rapid and undesirably the resulting coating
liquid decreases in continuous productivity and preservability. The mixing
ratio of water to silicon alkoxide (molar ratio) is preferably at least 2.
If a value of this ratio is less than 2, unreacted silicon alkoxide
remains in the resulting coating which will undesirably decrease in
adhesion to substrate, scratch resistance and alkali resistance. The
partial hydrolysis temperature employed is preferably
30.degree.-60.degree. C.
The fifth coating liquid for forming conductive coating of the present
invention illustrated above may be prepared by adding the
dialkoxy-bisacetylacetonato zirconium to a mixture of water and the
organic solvent in which the conductive substance has been dispersed,
thereby improving dispersibility and heat stability of the conductive
substance, and then incorporating the resulting mixture with the partial
hydrolysate of silicon alkoxide or its derivative. The incorporation of
the partial hydrolysate of silicon alkoxide or its derivative into the
above-mentioned mixture, prior to the addition of the
dialkoxy-bisacetylacetonato zirconium to said mixture, is not desirable
since the conductive substance dispersed in the mixture comes to
agglomerate.
The coating liquid for forming transparent conductive coating thus prepared
has such advantages as will be mentioned below. First, the conductive
coating formed therefrom is excellent in transparency and electrical
conductivity since the conductive substance dispersed in the coating
liquid is left in a monodisperse state by the protective colloidal action
of the dialkoxy-bisacetylacetonato zirconium added to said coating liquid.
Second, the coating liquid is improved in stability and hence no gellation
thereof occur and the stabilized coating liquid can be preserved for a
long period of time even at room temperature of about 30.degree. C.
Furthermore, the dialkoxy-bisacetylacetonato zirconium together with the
partial hydrolysate of silicon alkoxide or its derivative forms a matrix
of the resulting conductive coating, whereby said coating is increased in
scratch resistance and alkali resistance, and because of the presence of
said dialkoxy-bisacetylacetonato zirconium and said partial hydrolysate of
silicon alkoxide or its derivative in the coating liquid, a desired
conductive coating can be formed when said coating liquid as applied is
heated at the temperature of about 150.degree. C., and the conductive
coating further improved in electrical conductivity is obtained when the
coating liquid is heated at above 200.degree. C.
In the fifth coating liquid for forming conductive coating of the present
invention which contains the components as illustrated above, the
dialkoxy-bisacetylacetonato zirconium and the conductive substance are
preferably used in such an amount so that the ZrO.sub.2 /MO.sub.x weight
ratio of these two components in terms of oxide is 0.01-1 (MO.sub.x
represents the conductive substance as an oxide). If a value of this ratio
is less than 0.01, undesirably the conductive substance decreases in
dispersibility and heat stability, the resulting conductive coating
becomes poor in transparency and adhesion to a substrate, and the coating
liquid becomes poor in preservability and continuous productivity. If this
value exceeds 1, on one hand, undesirably the resulting conductive coating
becomes poor in transparency and adhesion to a substrate and decreases in
electrical conductivity.
The dialkoxy-bisacetylacetonato zirconium and silicon alkoxide are
preferably used in such an amount so that the ZrO.sub.2 /SiO.sub.2 weight
ratio of these two components in terms of oxide is 0.05-1. If a value of
this ratio is less than 0.05, the resulting conductive coating is not
sufficient in alkali resistance and, on one hand, if this value exceeds 1,
undesirably the resulting conductive coating decreases in adhesion to
substrate and transparency.
The dialkoxy-bisacetylacetonato zirconium and silicon alkoxide are
preferably used in such an amount so that the ZrO.sub.2 /SiO.sub.2 weight
ratio of these two components in terms of oxide is 0.05-1. If a value of
this ratio is less than 0.05, undesirably the resulting conductive coating
is not sufficient in alkali resistance and, on one hand, if this value
exceeds 1, the resulting conductive coating decreases in adhesion to a
substrate and transparency.
The conductive substance and other two components are preferably used in
such an amount so that the MO.sub.x /(SiO.sub.2 +ZrO.sub.2) weight ratio
of the components in terms of oxide is 0.5-5. If a value of this ratio is
less than 0.5, undesirably the resulting conductive coating is not
sufficient in electrical conductivity and, on one hand, if this value
exceeds 5, the resulting conductive coating decreases in adhesion to a
substrate, transparency and scratch resistance.
Furthermore, if the solids concentration (MO.sub.- +SiO.sub.2 +ZrO.sub.2)
in the coating liquid is less than 15% by weight, the conductive coating
answering the objects of the present invention may be obtained. If the
above-mentioned solids concentration exceeds 15% by weight, undesirably
the coating liquid becomes poor in preservability. If this solids
concentration is excessively low, it becomes necessary to repeat the
coating operation several times in order to the desired conductive
coating, and hence a practically useful solids concentration is at least
0.1% by weight.
The thus obtained first to fifth coating liquids for forming conductive
coatings of the present invention are coated on substrates such as glass
or plastics according to the conventionally known methods such as spinner,
spray, bar coater, role coater and the like methods. Subsequently, a film
of the coating formed on the substrate is dried to cure at a temperature
of from ordinary temperature to about 120.degree. C., whereby the desired
conductive coating excellent in adhesion to the substrate, scratch
resistance and transparency is obtained. When the conductive coating thus
obtained is further heated, the resulting coating is further improved in
permanence properties such as alkali resistance and the like.
The substrate on which a transparent conductive coating has been formed,
said conductive coating comprising zirconium oxide, conductive substance
and silicon oxide, has a glossiness of less than 190% as measured at an
angle of measurement of 60.degree. according to the method of measurement
of glossiness stipulated in JIS K 7105-81, such excellent electrical
conductivity as evidenced by its surface resistivity of 10.sup.3
-10.sup.11 .OMEGA./.quadrature., such excellent transparency as evidenced
by its total light transmittance of at least 80% and haze of less than 10%
and, moreover, has excellent permanence properties such as adhesion to the
substrate, scratch resistance, alkali resistance and the like.
The display device of the present invention and process for manufacturing
the same are illustrated hereinafter.
The present display device comprises a face-plate as a substrate, on the
surface of which a transparent conductive coating has been formed, said
transparent conductive coating comprising zirconium oxide, silicon oxide
and a conductive substance, and said face-plate having a glossiness of
30-100% as measured at an angle of measurement of 60.degree. according to
the method of measurement of glossiness stipulated in JIS K 7105-81, a
resolving power of at least 50 bars/cm, and a surface resistivity of
10.sup.3 -10.sup.11 .OMEGA./.quadrature..
The glossiness of the face-plate is represented by a value of glossiness as
measured at an angle of measurement of 60.degree. according to the method
of measurement of glossiness stipulated in JIS K7105-81, as mentioned
above. If this value is less than 30%, undesirably the face-plate
decreases in transparency and, on one hand, if the value exceeds 90%,
regular reflection of the coating is not decreased and the face-plate
glares, therefore the glossiness is preferably less than 90%, though the
upper limit of this value is not particularly defined.
The face-plate has a resolving power of at least 50 bars/cm, as mentioned
above. If this value is less than 50 bars/cm, undesirably the face-plate
becomes poor in transparency.
In the present specification, the resolving power of the face-plate was
expressed by way of the number of bars per cm in a bar chart, said number
of bars being capable of being counted distinctly by visual observation of
the chart. That is, the resolving power is determined by using a box of 50
by 30 centimeters wherein a face-plate having attached a bar chart as
shown in FIG. 1 to the side on which no coating is coated is arranged at
one wall of the box in the manner as shown in FIG. 2 so that the coated
side of the panel faces outward, and the face-plate thus arranged is
visually observed at a distance of 30 cm from the coated side to count the
number of bars per cm in the bar chart that can be distinctly confirmed.
In that case, the box is provided with 20 W fluorescent lamps at both ends
of the other wall of the box provided with no face-plate, and the surface
of the wall of the box provided with no face-plate is colored white. The
bar chart used included those in which the number of bars is increased
every 5 bars/cm, for example, 10 bars/cm, 15 bars/cm, 20 bars/cm, 25
bars/cm and the like.
In the bar charts thus used, 1 is a bar printed, 2 is a space between the
printed bars, and a width a of the printed bar is equal to a width b of
the space.
In the display device of the present invention, an average surface
roughness Rz (a ten-point average roughness as measured in accordance with
JIS B0601-82) of the face-plate is 0.2-5 .mu.m, preferably 0.2-3 .mu.m. If
this average surface roughness is less than 0.2 .mu.m, undesirably the
face-plate decreases in non-glare and no sufficient antistatic effect is
obtained, though the plate is excellent in resolving power and
transparency and, on one hand, if the average surface roughness exceeds 5
.mu.m, undesirably the face-plate decreases in resolving power and
transparency.
The present display device may be prepared by using the second to fifth
coating liquids for forming conductive coatings of the present invention
mentioned previously.
That is, the face-plate of the present display device may be prepared by
coating a face-plate previously heated to and kept at
40.degree.-90.degree. C., preferably 50.degree.-70.degree. C., with any of
the second to fifth coating liquids for forming conductive coatings of the
present invention by the spray method, followed by drying and/or heating.
If a heating temperature of the face-plate is less than 40.degree. C.,
undesirably the liquid components of the coating liquid as coated will not
dry sufficiently and undergo leveling, whereby no non-glare coating is
obtained and, on one hand, if this temperature exceeds 90.degree. C.,
undesirably the liquid components will dry rapidly, whereby the resulting
coating becomes poor in adhesion to the plate, transparency and permanence
properties. When the coating liquid is coated on the face-plate by the
spray method, therefore, the coating amount, coating speed and air
pressure supplied to the spray should be controlled so that the heating
temperature of the face-plate does not deviate from the above-mentioned
temperature range.
Subsequently, the display device of the present invention is obtained by
drying the front panel thus coated by the spray method with the coating
liquid for forming conductive coating. When a coating having higher
permanence properties and mechanical strength is needed, such coating may
be obtained by heating the face-plate as coated in the manner now
described at a temperature of above 200.degree. C. but below the glass
transition point of the face-plate. In that case, the heating operation
may be repeated many times so long as the heating temperature employed is
below the glass transition point of the face-plate. In cases where
non-glare is not needed according to the purpose for which the display
device is used, a desired coating having lesser non-glare or substantially
no non-glare may be obtained by varying the spray conditions to be
employed.
Furthermore, the face-plate of the display device of the present invention
may be prepared by coating the coating liquid for forming conductive
coating on a front panel by the spray method in the manner now described,
drying and/or heating the thus coated face-plate, coating by the spray
method a coating liquid comprising transparent protective components on
the thus dried and/or heated face-plate at 40.degree.-90.degree. C., and
then drying and/or heating the thus coated face-plate.
Usable as the coating liquid comprising transparent protective components
are the second to fifth coating liquids for forming conductive coatings,
from which the conductive substance has been excluded.
As the coating liquid comprising transparent protective components,
moreover, there may also be used a liquid prepared by homogeneously
dissolving or dispersing a binder resin in an organic solvent. Useful
binder resins include silicon resins, melamine resins, urethane resins and
the like.
The present invention is illustrated below with reference to examples, but
it should be construed that the invention is in no way limited to those
examples.
EXAMPLE 1
Preparation of Conductive Tin Oxide Sol
A starting solution was prepared by dissolving 316 g of potassium stannate
and 38.4 g of tartar emetic in 686 g of water. The starting solution
together with nitric acid was added over 12 hours to 1000 g of water
warmed at 50.degree. C. with stirring and subjected to hydrolysis while
maintaining a pH of the system at 8.5, whereby a sol liquid was obtained.
Colloidal particles were separated by filtration from the sol washed to
remove by-product salts therefrom, dried, calcined at 350.degree. C. for 3
hours in air, and then further calcined at 650.degree. C. for 2 hours in
air to obtain fine powder (I). To 1600 g of an aqueous hydroxide solution
(containing 40 g of KOH) was added 400 g of the fine powder (I), and the
mixture kept at 30.degree. C. was stirred for 3 hours with a sand mill to
obtain conductive tin oxide colloid.
Subsequently, this conductive tin oxide colloid was treated with an ion
exchange resin to obtain dealkalized conductive tin oxide colloid (a
conductive sol). This dealkalized conductive sol contained no precipitate,
has a solids concentration of 20% by weight and colloidal particles having
an average particle diameter of 0.07 .mu.m. The amount of colloidal
particles having a particle diameter of less than 0.1 .mu.m was 87% of the
total amount of colloidal particles.
In this connection, the measurement of average particle diameter of the
colloidal particles was conducted with an ultracentrifugal particle size
distribution analyzer (CAPA-500 manufactured and sold by Horiba Seisakusho
K. K.), wherein a test specimen was adjusted to a solids concentration of
0.5% by weight and subjected to centrifugal sedimentation at 5000 rpm.
(The same shall apply hereinafter).
A mixture comprising 250 g of the conductive sol obtained above, 225 g of
N-methyl-2-pyrrolidone (hereinafter called NMP) and 100 g of an aqueous
solution of 25% by weight of zirconium oxychloride in terms of ZrO.sub.2
(hereinafter called ZOC) was heated at 80.degree. C. with a rotary
evaporator under reduced pressure, thereby distilling off 75 g of water.
The liquid obtained was cooled and then thoroughly mixed with 1000 g of a
mixture of MeOH/BuOH (1/1 weight ratio) to obtain a coating liquid for
forming conductive coating.
EXAMPLE 2
A mixture comprising 100 g of the conductive sol obtained in Example 1, 45
g of NMP and 20 g of ZOC was heated at 80.degree. C. with a rotary
evaporator under reduced pressure to distill off 15 g of water. The liquid
obtained was cooled and thoroughly mixed with 350 g of a mixture of
MeOH/EtOH (1/1 weight ratio) to obtain a coating liquid for forming
conductive coating.
EXAMPLE 3
Following substantially the same procedure as described in Example 1, a
coating liquid for forming conductive coating was obtained, except that in
place of the ZOC used in Example 1, there was used an aqueous solution of
zirconium oxynitrate (hereinafter called ZON) containing 25% by weight of
ZON in terms of ZrO.sub.2.
EXAMPLE 4
A homogeneous mixture comprising 100 g of the conductive sol obtained in
Example 1, 90 g of NMP and 40 g of ZOC was heated at 80.degree. C. with a
rotary evaporator under reduced pressure to distill off 15 g of water. The
liquid obtained was cooled and thoroughly mixed with 2800 g of a mixture
of MeOH/EtOH (1/1 weight ratio) to obtain a coating liquid for forming
conductive coating.
EXAMPLE 5
A homogeneous mixture comprising 250 g of the conductive sol obtained in
Example 1, 150 g of NMP and 100 g of ZOC was heated at 80.degree. C. with
a rotary evaporator under reduced pressure and thoroughly mixed with 425 g
of a mixture of MeOH/EtOH (1/1 weight ratio) to obtain a coating liquid
for forming conductive coating.
EXAMPLE 6
Following substantially the same procedure as described in Example 1, a
coating liquid for forming conductive coating was obtained, except that in
place of the NMP used in Example 1, there was used 225 g of methyl
cellosolve.
EXAMPLE 7
Following substantially the same procedure as described in Example 1, a
coating liquid for forming conductive coating was obtained, except that in
place of the NMP used in Example 1, there was used 225 g of ethylene
glycol.
EXAMPLE 8
Following substantially the same procedure as described in Example 1, a
coating liquid for forming conductive coating was obtained, except that in
place of the NMP used in Example 1, there was used 225 g of
N,N-dimethylformamide.
EXAMPLE 9
A mixture comprising 83.3 g of a liquid prepared by diluting the conductive
sol liquid obtained in Example 1 with water to 12% by weight, 60 g of NMP,
100 g of 5% by weight of ZOC in terms of ZrO.sub.2, and 256.7 g of a
mixture of MeOH/EtOH (1/1 weight ratio) was thoroughly blended to obtain a
coating liquid for forming coating.
EXAMPLE 10
A mixture of 50 g of the fine powder (I) obtained in Example 1 and 200 g of
water was fed to a sand mill, and the mixture was subjected for 3 hours to
pulverization with media of 1-2 mm .phi. media. After the pulverization,
an average particle diameter of particles in the liquid was 0.25 .mu.m.
Following substantially the same procedure as described in Example 1, a
coating liquid for forming conductive coating was obtained except that
there was used the conductive sol dispersion obtained in the manner now
described was used.
EXAMPLE 11
To a sand mill was fed a mixture comprising 50 g of the fine powder (I)
obtained in Example 1, which had been classified into the powder having a
particle diameter of less than 1 .mu.m, and 200 g of water, and the
mixture was subjected to pulverization for 3 hours with 0.3-1 mm .phi.
media to obtain a conductive tin oxide dispersion. Following substantially
the same procedure as described in Example 1, a coating liquid for forming
conductive coating was obtained except that there was used the conductive
tin oxide dispersion obtained above was used.
In this connection, an average particle diameter of particles in the
dispersion after the pulverization was 0.08 .mu.m, and the amount of
particles having a particle diameter of less than 0.1 .mu.m was 65% of the
amount of total particles.
EXAMPLE 12
There were prepared a solution of 79.9 g of indium nitrate in 686 g of
water and a solution of 12.7 g of potassium stannate in an aqueous
solution of 10% by weight of potassium stannate. Both indium nitrate and
potassium stannate solutions obtained above were added to 1000 g of water
warmed at 50.degree. C. with stirring and subjected to hydrolysis while
maintaining a pH of the system at 11, whereby a sol was obtained.
Colloidal particles present in the sol were separated therefrom by
filtration, washed to remove by-product salts therefrom, dried, calcined
at 350.degree. C. for 3 hours in air, and then further calcined at
600.degree. C. for 2 hours in air to obtain a fine powder (II).
Following substantially the same procedure as described in Example 10, a
coating liquid for forming conductive coating was obtained except that 50
g of the fine powder (II) obtained above was used.
In this connection, an average particle diameter of particles in the
dispersion after pulverization was 0.29 .mu.m.
COMPARATIVE EXAMPLE 1
A homogeneous mixture comprising 25 g of the conductive sol obtained in
Example 1, 90 g of NMP and 40 g of ZOC was heated at 80.degree. C. under
reduced pressure with a rotary evaporator to distill off 25 g of water.
The liquid obtained was cooled and thoroughly mixed with 170 g of a
mixture of MeOH/EtOH (1/1 weight ratio) to obtain a coating liquid for
forming conductive coating.
COMPARATIVE EXAMPLE 2
A homogeneous mixture comprising 175 g of the conductive sol obtained in
Example 1, 45 g of NMP and 20 g of ZOC was heated at 80.degree. C. under
reduced pressure with a rotary evaporator to distill off 14 g of water.
The liquid obtained was cooled and thoroughly mixed with 574 g of a
mixture of MeOH/EtOH (1/1 weight ratio) to obtain a coating liquid for
forming conductive coating.
COMPARATIVE EXAMPLE 3
A homogeneous mixture comprising 250 g of the conductive sol obtained in
Example 1, 4 g of NMP and 100 g of ZOC was heated at 80.degree. C. under
reduced pressure, and 200 g of water was distilled off therefrom,
whereupon gellation occurred.
COMPARATIVE EXAMPLE 4
A mixture comprising 100 g of the conductive sol obtained in Example 1,
which had been diluted with water to 10% by weight, 60 g of NMP, 100 g of
3% by weight of ZOC in terms of ZrO.sub.2, and 256.7 g of a mixture of
MeOH/EtOH (1/1 weight ratio) was thoroughly mixed to obtain a coating
liquid for forming conductive coating.
In Table 1, the composition of liquid and ratio of components used in each
of the foregoing examples and comparative examples were shown.
Using a spinner operated at a rate of 2000 rpm, coated individually on a
glass plate were the coating liquids for forming conductive coatings
obtained respectively in Examples 1-7, 9, 11 and 12, and Comparative
Examples 1, 2 and 4, and on an acrylic resin plate was the coating liquid
for forming conductive coating obtained in Example 8.
Respective coatings were obtained on the glass plates thus coated by drying
them at 110.degree. C. for 10 minutes, followed by heating at 300.degree.
C. for 30 minutes, and on the acrylic resin plate thus coated by drying at
110.degree. C. for 30 minutes. Evaluation of the coatings thus obtained
was conducted with respect to the test items mentioned below.
The results obtained are shown in Tables 2 and 3.
(1) Transparency: Total light transmittance (Tt) and haze (H) were measured
with a haze computer (manufactured and sold by Suga Shikenki K.K.).
(2) Glossiness: Glossiness (G) was measured at an angle of measurement of
60.degree. C. in accordance with the method of measurement of glossiness
stipulated in JIS K7105-81. This glossiness is represented by a relative
value of the test specimen to the reflactance of the standard plate, and
stands in such relationships that the higher is the reflactance, the
higher is the glossiness, and the lower is the reflactance, the lower is
the glossiness.
(3) Adhesion: A part of piece of commercially available cellophane tape of
12 mm in width was allowed to stick on the coating while holding the
remaining part of the tape perpendicular to the coating, and then the tape
is instantaneously peeled off therefrom to visually observe whether the
coating remained undetached or not.
(4) Hardness: Hardness of the coating was measured by subjecting to the
pencil hardness test stipulated in JIS D0202-71.
(5) Surface resistivity: Surface resistivity of the coating was measured
with an electrode cell (manufactured and sold by YHP).
(6) Permanence properties: The coated plate was immersed in the following
four kinds of liquids to evaluate adhesion of the coating to the plate,
and the glossiness and surface resistivity of the coating as determined
before the test with those as measured after the test.
1) Immersion of the plate in 15% by weight aqueous ammonia solution at room
temperature for 120 hours.
2) Immersion of the plate in 10% by weight aqueous NaCl solution at room
temperature for 120 hours.
3) Immersion of the plate in boiling water for 30 minutes.
4) Immersion of the plate is 50% by weight aqueous acetic acid solution at
room temperature for 120 hours.
TABLE 1
__________________________________________________________________________
Ratio of components
Composition of liquid Solids
Par-
Particle
Stabi-
Organic content
ticle H.sub.2 O
Stabi-
Stabilizer
ZrO.sub.2
(Note 1)
H.sub.2 O
lizer
solvent
Total
(Note 2)
ZrO.sub.2
H.sub.2 O
ZrO.sub.2
lizer
ZrO.sub.2
Pot life
(g) (g) (g)
(g) (g) (g) (wt %)
(g/g)
(wt %)
(g/g)
(wt %)
(mol/mol)
(R.
__________________________________________________________________________
T)
Example
1 25.0
50.0 200.0
225.0
1000.0
1500.0
5.0 2.0 13.3
8.0 15.0
11.2 >3 months
2 5.0
20.0 80.0
45.0
350.0
500.0
5.0 4.0 16.0
16.0
9.0
11.2 >3 months
3 25.0
50.0 200.0
225.0
1000.0
1500.0
5.0 2.0 13.3
8.0 15.0
11.2 >3 months
4 10.0
20.0 80.0
90.0
2800.0
3000.0
1.0 2.0 2.7
8.0 3.0
11.2 >3 months
5 25.0
50.0 100.0
150.0
425.0
750.0
10.0 2.0 13.3
4.0 20.0
7.5 >3 months
6 25.0
50.0 200.0
225.0
1000.0
1500.0
5.0 2.0 13.3
8.0 15.0
14.6 >3 months
7 25.0
50.0 200.0
225.0
1000.0
1500.0
5.0 2.0 13.3
8.0 15.0
17.9 >3 months
8 25.0
50.0 200.0
225.0
1000.0
1500.0
5.0 2.0 13.3
8.0 15.0
15.1 >3 months
9 5.0
10.0 168.3
60.0
256.7
500.0
3.0 2.0 33.7
33.7
12.0
14.9 >3 months
10 25.0
50.0 200.0
225.0
1000.0
1500.0
5.0 2.0 13.3
8.0 15.0
11.2 >3 months
11 25.0
50.0 200.0
225.0
1000.0
1500.0
5.0 2.0 13.3
8.0 15.0
11.2 >3 months
12 25.0
50.0 200.0
225.0
1000.0
1500.0
5.0 2.0 13.3
8.0 15.0
11.2 >3 months
Compar.
Example
1 10.0
5.0 25.0
90.0
170.0
300.0
5.0 0.5 8.3
2.5 30.0
11.2 >3 months
2 5.0
35.0 141.1
45.0
574.0
800.0
5.0 7.0 17.6
28.2
5.6
11.2 >3 months
3 25.0
50.0 75.0
4.0
-- -- -- 2.0 -- 3.0 -- 0.2 gelation
4 3.0
10.0 187.0
15.0
218.0
433.0
3.0 3.3 43.2
62.3
3.5
6.2 >3
__________________________________________________________________________
months
(Note 1) Particle: Conductive substance
(Note 2) Solids content: (ZrO.sub.2 + conductive substance)/(ZrO.sub.2 +
conductive substance + H.sub.2 O + stabilizer + diluent)
TABLE 2
______________________________________
Transparency Glossiness
Surface
Item Tt H G resistivity
Adhe- Hard-
No. (%) (%) (%) (.OMEGA./.quadrature.)
sion ness
______________________________________
Example
1 91.5 2.0 136 3 .times. 10.sup.6
.smallcircle.
>9H
2 91.0 2.0 131 8 .times. 10.sup.5
.smallcircle.
>9H
3 92.0 2.0 140 1 .times. 10.sup.6
.smallcircle.
>9H
4 92.5 1.5 131 8 .times. 10.sup.6
.smallcircle.
>9H
5 90.0 3.0 126 5 .times. 10.sup.5
.smallcircle.
>9H
6 91.0 2.0 134 5 .times. 10.sup.6
.smallcircle.
>9H
7 91.3 2.0 130 2 .times. 10.sup.6
.smallcircle.
>9H
8 91.0 2.0 133 1 .times. 10.sup.6
.smallcircle.
8H
9 92.2 2.5 125 5 .times. 10.sup.6
.smallcircle.
>9H
10 89.0 6.5 89 2 .times. 10.sup.7
.smallcircle.
9H
11 91.8 1.8 138 2 .times. 10.sup.6
.smallcircle.
>9H
12 84.0 8.8 78 2 .times. 10.sup.4
.smallcircle.
9H
Compar.
Ex.
1 92.0 2.0 145 .sup. 1 .times. 10.sup..sup.11
.smallcircle.
>9H
2 90.0 3.0 125 2 .times. 10.sup.8
x 7H
______________________________________
Adhesion: The specimen was rated .smallcircle. when its coating did not
peel off, and rated x when the coating peeled off.
TABLE 3
__________________________________________________________________________
Aqueous Boiling
Aqueous
No. Item ammonia
NaCl water acetic acid
__________________________________________________________________________
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
1 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
2 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
3 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
4 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
5 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
6 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
7 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
146 No change
.rarw. .rarw.
8 Surface resistivity (.OMEGA./.quadrature.)
No-change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
9 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
10 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
11 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Example
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
12 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw.
.rarw. .rarw.
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Compar.
Ex. 1
Glossiness (%)
No change
.rarw.
.rarw. .rarw.
Surface resistivity (.OMEGA./.quadrature.)
5 .times. 10.sup.1
4 .times. 10.sup.10
2 .times. 10.sup.11
2 .times. 10.sup.10
Adhesion .smallcircle.
.rarw.
.rarw. .rarw.
Ex. 2
Glossiness (%)
Peeled No-change
Peeled No change
Surface resistivity (.OMEGA./.quadrature.)
10.sup.13 or more
5 .times. 10.sup.8
10.sup.13 or more
2 .times. 10.sup.8
Adhesion x .rarw.
.rarw. .rarw.
__________________________________________________________________________
The specimen which did not change before and after the test was denoted
"no change", and when it changed, a numerical value measured after the
test was indicated.
EXAMPLE 13
Into a hydrogen type ion exchange resin column was passed through at a
space velocity of SV=5, 2000 g of an aqueous solution contain 5% by weight
of sodium silicate in terms of SiO.sub.2 of (SiO.sub.2 /Na.sub.2 O=3
moles/mole) while keeping at 15.degree. C., whereby a non-sedimentary
silica dispersion was obtained. This non-sedimentary silica dispersion as
obtained was diluted with water to 2% by weight and subjected for 1 hour
to centrifugal sedimentation at 250,000 G, whereupon the precipitates
formed were 8% by weight based on the total amount of SiO.sub.2.
A mixture comprising 50 g of the non-sedimentary silica dispersion obtained
above, 50 g of the conductive sol obtained in Example 1, 20 g of NMP, 10 g
of ZOC and 170 g of MeOH/BtOH (1/1 weight ratio) was thoroughly mixed to
obtain a coating liquid for forming conductive coating.
EXAMPLE 14
A mixture comprising 50 g of the non-sedimentary silica dispersion obtained
in Example 13, 200 g of the conductive sol obtained in Example 1, 10 g of
NMP, 40 g of ZOC and 1400 g of MeOH/EtOH (1/1 weight ratio) was thoroughly
mixed to obtain a coating liquid for forming conductive coating.
EXAMPLE 15
Following substantially the same procedure as described in Example 13, a
coating liquid for forming conductive coating was obtained except that 10
g of the NMP and 380 g of MeOH/BuOH (1/1 weight ratio) were used.
EXAMPLE 16
A mixture comprising 50 g of the non-sedimentary silica dispersion obtained
in Example 13, 220 g of the conductive sol obtained in Example 1, 110 g of
NMP, 100 g of ZOC and 345 g of MeOH/EtOH (1/1 weight ratio) was thoroughly
mixed to obtain a coating liquid for forming conductive coating.
EXAMPLE 17
A homogeneous mixture comprising 50 g of the non-sedimentary silica
dispersion obtained in Example 13, 100 g of the conductive sol obtained in
Example 1, 150 g of N,N-dimethylformamide and 30 g of ZOC was heated at
80.degree. C. under reduced pressure with a rotary evaporator to distill
off 135 g of water. The liquid obtained was cooled and thoroughly mixed
with 405 g of MeOH/BuOH (1/1 weight ratio) to obtain a coating liquid for
forming conductive coating.
EXAMPLE 18
Following substantially the same procedure as described in Example 13, a
coating liquid for forming conductive coating was obtained except that in
place of the NMP used in Example 13, there was used 20 g of methyl
cellosolve.
EXAMPLE 19
Following substantially the same procedure as described in Example 13, a
coating liquid for forming conductive coating was obtained except that in
place of the NMP used in Example 13, there was used 20 g of morpholine.
COMPARATIVE EXAMPLE 5
A homogeneous mixture comprising 200 g of the non-sedimentary silica
dispersion obtained in Example 13, 125 g of the conductive sol obtained in
Example 1, 50 g of NMP and 10 g of ZOC was heated at 80.degree. C. under
reduced pressure with a rotary evaporator to distill off 210 g of water.
The liquid obtained was cooled and thoroughly mixed with MeOH/BuOH (1/1
weight ratio) to obtain a coating liquid for forming conductive coating.
COMPARATIVE EXAMPLE 6
A mixture comprising 100 g of the non-sedimentary silica dispersion
obtained in Example 13, 25 g of the conductive sol obtained in Example 1,
40 g of NMP, 20 g of ZOC and 115 g of MeOH/BuOH (1/1 weight ratio) was
thoroughly mixed to obtain a coating liquid for forming conductive
coating.
COMPARATIVE EXAMPLE 7
A homogeneous mixture comprising 100 g of the non-sedimentary silica
dispersion obtained in Example 13, 350 g of the conductive sol obtained in
Example 1, 40 g of NMP and 20 g of ZOC was heated at 80.degree. C. under
reduced pressure with a rotary evaporator to distill off 250 g of water.
The liquid obtained was cooled and thoroughly mixed with 1340 g of
MeOH/BuOH (1/1 weight ratio) to obtain a coating liquid for forming
conductive coating.
COMPARATIVE EXAMPLE 8
A homogeneous mixture comprising 500 g of the non-sedimentary silica
dispersion obtained in Example 13, 500 g of NMP and 100 g of ZOC was
heated at 80.degree. C. under reduced pressure with a rotary evaporator to
distill off 900 g of water, whereupon gellation occurred.
COMPARATIVE EXAMPLE 9
A mixture comprising 100 g of the non-sedimentary silica dispersion
obtained in Example 13, 100 g of the conductive sol obtained in Example 1,
25 g of NMP, 100 g of an aqueous solution containing 5% by weight of ZOC
in terms of ZrO.sub.2 and 75 g of MeOH/BuOH (1/1 weight ratio) was
thoroughly mixed to obtain a coating liquid for forming conductive
coating.
In Table 4, the composition of liquid and ratio of components used in each
of the foregoing examples and comparative examples were shown.
Using a spinner operated at a rate of 2000 rpm, coated individually on a
glass plate were the coating liquids for forming conductive coatings
obtained respectively in Examples 13-17 and Comparative Examples 5-7, and
9, and on an acrylic resin plate were the coating liquids for forming
conductive coatings obtained in Examples 18 and 19. Respective coatings
were obtained on the glass plates thus coated by drying at 110.degree. C.
for 10 minutes, followed by heating at 300.degree. C. for 30 minutes, and
on the acrylic resin plates thus coated by drying them at 110.degree. C.
for 30 minutes.
The coatings thus formed were evaluated in the same manner as in Example 1.
The results obtained are shown in Tables 5 and 6, respectively.
TABLE 4
__________________________________________________________________________
Composition of liquid
Conductive
ZrO.sub.2 (g)
SiO.sub.2 (g)
Colloid (g)
H.sub.2 O (g)
Stabilizer (g)
Organic Solvent (g)
Total Wt. (g)
__________________________________________________________________________
Example
13 2.5 2.5 10.0 95.0 20.0 170.0 300.0
14 10.0 2.5 40.0 237.5
10.0 1400.0 1700.0
15 2.5 2.5 10.0 95.0 10.0 380.0 500.0
16 25.0 2.5 44.0 298.5
130.0 345.0 825.0
17 7.5 2.5 20.0 15.0 150.0 405.0 600.0
18 2.5 2.5 10.0 95.0 20.0 170.0 300.0
19 2.5 2.5 10.0 95.0 20.0 170.0 300.0
Compar.
Example
5 2.5 10.0 25.0 87.5 50.0 1075.0 1250.0
6 5.0 5.0 5.0 130.0
40.0 115.0 300.0
7 5.0 5.0 70.0 140.0
40.0 1340.0 1600.0
8 25.0 25.0 100.0 50.0 6.0
9 5.0 5.0 20.0 270.0
25.0 75.0 400.0
__________________________________________________________________________
Ratio of components
Solids
content Conductive
H.sub.2 O
weight
SiO.sub.2
particle
Total
H.sub.2 O
Stabilizer
Stabilizer
(Note 1)
ZrO.sub.2
ZrO.sub.2 + SiO.sub.2
weight
ZrO.sub.2
Total wt.
Total wt.
(wt %)
(g/g)
(g/g) (wt/%)
(g/g)
(wt/%)
(mol/mol)
Pot life
__________________________________________________________________________
Example
13 5.0 1.00
2.0 31.7 38.0
6.7 3.3 >3 months
14 3.1 0.25
3.2 14.0 23.8
0.6 0.8 >3 months
15 3.0 1.00
2.0 19.0 38.0
2.0 1.6 >3 months
16 8.7 0.10
1.6 36.2 11.9
13.3 4.5 >3 months
17 5.0 0.33
2.0 2.5 2.0
25.0 20.0 >3 months
18 5.0 1.00
2.0 31.7 38.0
6.7 4.3 >3 months
19 5.0 1.00
2.0 31.7 38.0
6.7 3.7 >3 months
Compar.
Example
5 3.0 4.0 2.0 7.0 135.0
4.0 2.7 >3 months
6 5.0 1.0 0.5 43.3 26.0
13.3 3.3 >3 months
7 5.0 1.0 7.0 8.8 28.0
2.5 3.3 >3 months
8 1.0 2.0 2.0 0.1 gelation
9 7.5 1.0 2.0 67.5 54.0
6.3 2.0 > 3 months
__________________________________________________________________________
(Note 1) Solids content (ZrO.sub.2 + SiO.sub.2 + Conductive tin oxide
colloid)
Percentage of solids: Solids weight/Total weight
TABLE 5
__________________________________________________________________________
Transparency Gloss-
Surface
Item Tt H iness
resistivity
Adhe- Coating
No. (%)
(%) G (%)
(.OMEGA./.quadrature.)
sion
Hardness
process
__________________________________________________________________________
Example
13 93.2
2.0 135 5 .times. 10.sup.5
.smallcircle.
>9H Spinner
14 92.0
2.5 138 7 .times. 10.sup.6
.smallcircle.
>9H Spinner
15 93.0
2.0 133 8 .times. 10.sup.6
.smallcircle.
>9H Spinner
16 90.0
3.0 128 4 .times. 10.sup.5
.smallcircle.
>9H Spinner
17 91.5
2.0 138 5 .times. 10.sup.6
.smallcircle.
>9H Spinner
18 92.5
2.0 133 3 .times. 10.sup.7
.smallcircle.
8H Spinner
19 92.0
2.5 136 4 .times. 10.sup.7
.smallcircle.
8H Spinner
Compr.
Ex.
5 93.0
1.5 130 5 .times. 10.sup.6
.smallcircle.
>9H Spinner
6 92.0
1.5 138 .sup. 5 .times. 10.sup.11
.smallcircle.
>9H Spinner
7 89.0
3.5 123 8 .times. 10.sup. 7
x 7H Spinner
__________________________________________________________________________
Adhesion: The specimen rated .smallcircle. when its coating did not peel
off, and rated x when the coating peeled off.
TABLE 6
__________________________________________________________________________
Aqueous Boiling
Aqueous
No. Item ammonia
NaCl water acetic acid
__________________________________________________________________________
Glossiness (%)
No change
.rarw. .rarw. .rarw.
Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw. .rarw. .rarw.
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Example
Glossiness (%)
No change
.rarw. .rarw. .rarw.
13b Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw. .rarw. .rarw.
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Example
Glossiness (%)
No change
.rarw. .rarw. .rarw.
14 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw. .rarw. .rarw.
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Example
Glossiness (%)
No change
.rarw. .rarw. .rarw.
15 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw. .rarw. .rarw.
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Example
Glossiness (%)
No change
.rarw. .rarw. .rarw.
16 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw. .rarw. .rarw.
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Example
Glossiness (%)
No change
.rarw. .rarw. .rarw.
17 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw. .rarw. .rarw.
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Example
Glossiness (%)
No change
.rarw. .rarw. .rarw.
18 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw. .rarw. .rarw.
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Example
Glossiness (%)
No change
.rarw. .rarw. .rarw.
19 Surface resistivity (.OMEGA./.quadrature.)
No change
.rarw. .rarw. .rarw.
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Compar.
Glossiness (%)
95 110 108 No change
Ex. 5
Surface resistivity (.OMEGA./.quadrature.)
1 .times. 10.sup.11
.rarw. .rarw. No change
Adhesion x .rarw. .rarw. .smallcircle.
Compar.
Glossiness (%)
No change
.rarw. .rarw. .rarw.
Ex. 6
Surface resistivity (.OMEGA./.quadrature.)
6 .times. 10.sup.10
9 .times. 10.sup.9
6 .times. 10.sup.11
3 .times. 10.sup.11
Adhesion .smallcircle.
.rarw. .rarw. .rarw.
Compar.
Glossiness (%)
Peeled off
Peeled off
Peeled off
No change
Ex. 7
Surface resistivity (.OMEGA./.quadrature.)
10.sup.13 or more
10.sup.13 or more
10.sup.13 or more
5 .times. 10.sup.8
Adhesion x .rarw. .rarw. .rarw.
__________________________________________________________________________
The specimen which did not change before and after the test was denoted
"No change", and if it changed, a numerical value measured after the test
was indicated.
EXAMPLE 20
Preparation of coating liquid for forming conductive coating
A coating liquid (liquid A), which is a base liquid, was prepared by mixing
100 g of ethyl silicate 28, ethanol solution containing 28% by weight of
tetraethoxysilane in terms of SiO.sub.2) 112 g of ZON, 84 g of pure water
and 824 g of ethanol together with stirring.
A conductive tin oxide sol (liquid B) was prepared by mixing with stirring
560 g of the conductive sol obtained in Example 1 with 1,680 g of ethanol.
The liquids A and B thus obtained were mixed together to obtain a coating
liquid for forming conductive coating.
EXAMPLE 21
Following substantially the same procedure as described in Example 20, a
coating liquid for forming conductive coating was obtained except that the
liquids A and B used in Example 20 were replaced by those which contained
50 g of ethyl silicate 40 ethanol solution containing 40% by weight of
tetraethoxysilane in terms of SiO.sub.2) 10 g of ZOC, 688.5 g of a
methanol-butanol mixture (weight ratio=1:1) and 1.5 g of pure water, and
which contained 562.5 g of the conductive sol obtained in Example 1 and
3,187.5 g of a methanol-butanol mixture, respectively.
EXAMPLE 22
Following substantially the same procedure as described in Example 20, a
coating liquid for forming conductive coating was obtained except that the
liquids A and B used in Example 20 were replaced by those which contained
30 g of ethyl silicate 28, 55 g of ZON, and 137 g of a methyl
cellosolve-ethyl acetate mixture (weight ratio=1:1), and which contained
66.6 g of the conductive sol and 66.4 g of a methyl cellosolve-ethyl
acetate mixture, respectively.
EXAMPLE 23
Preparation of conductive tin oxide dispersion
The powder (I) obtained in Example 1 was dispersed in pure water, and the
dispersion was treated for 3, hours to obtain an aqueous dispersion of
conductive tin oxide having an average particle diameter of 0.2 .mu.m,
said dispersion having a solids concentration of 20% by weight.
Preparation of coating liquid for forming conductive coating
A mixture (liquid C) comprising 50 g of ethyl silicate 28, 137.8 g of ZOC,
16.8 g of pure water and 763.4 g of ethanol was prepared.
A mixture (liquid D) comprising 484 g of the conductive tin oxide
dispersion obtained above and 1936 g of ethanol was prepared.
The liquid C and liquid D were mixed together with stirring to obtain a
coating liquid for forming conductive coating.
EXAMPLE 24
Preparation of conductive indium oxide dispersion
The fine powder (II) obtained in Example 12 was dispersed in methyl
cellosolve, and the dispersion was treated for 3 hours with a sand mill to
obtain a methyl cellosolve dispersion of conductive indium oxide having an
average particle diameter of 0.3 .mu.m, said dispersion having a solids
concentration of 30% by weight.
Preparation of coating liquid for forming conductive coating
A mixture comprising 50 g of ethyl silicate 40, 295 g of ZON, 48 g of pure
water and 2733.5 g of methyl cellosolve was prepared. The above-mentioned
conductive indium oxide dispersion was further mixed thoroughly with 8842
g of methyl cellosolve, and then the mixture was mixed with stirring with
the above-mentioned mixture to obtain a coating liquid for forming
conductive coating.
EXAMPLE 25
Preparation of non-sedimentary silica dispersion
To the non-sedimentary silica dispersion obtained in Example 13 was added
and mixed therewith 44.5 g, based on 100 g of the non-sedimentary silica
dispersion, of NMP as a stabilized and the mixture was then heated at
80.degree. C. with a rotary evaporator to distill off the greater part of
water, whereby a stabilized non-sedimentary silica dispersion (liquid E)
was obtained. This liquid had the SiO.sub.2 concentration of 10% by weight
and the water content of 1.0% by weight.
Preparation of coating liquid for forming conductive coating
A mixture (liquid F) comprising 100 g of ethyl silicate 28, 112 g of ZON,
939 g of ethanol, 84 g of pure water and 31 g of the above-mentioned
liquid E.
Separately, a mixture (liquid G) comprising 591 g of the conductive sol
obtained in Example 1 and 1773 g of ethanol was prepared.
The liquids F and G were mixed together with stirring to obtain a coating
liquid for forming conductive coating.
EXAMPLE 26
Following substantially the same procedure as described in Example 25, a
coating liquid for forming conductive coating was obtained except that of
the components of the liquid F, the ethanol used was 1104 g and the liquid
E used was 280 g, and of the components of the liquid G, the conductive
sol used was 840 g and the ethanol used was 3192 g.
EXAMPLE 27
Following substantially the same procedure as described in Example 25, a
coating liquid for forming conductive coating was obtained except that of
the components of the liquid F, the ethanol used was 3344 g and the liquid
E used was 2520 g, and of the components of the liquid G, the conductive
sol used was 3080 g and the ethanol used was 9240 g.
Properties of the coating liquids for forming conductive coatings obtained
in the foregoing examples are shown in Table 7.
TABLE 7
__________________________________________________________________________
MO.sub.x /
ZrO.sub.2 /SiO.sub.2
(ZrO.sub.2 + SiO.sub.2
Solids conc.
SiO.sub.2 /SiO.sub.2
Example
(Molar ratio)
(weight ratio)
(wt %) (weight ratio)
pH
Pot life
__________________________________________________________________________
20 0.49 2.0 5.0 -- 1.5
3 months or more
21 0.06 5.0 3.0 -- 1.9
3 months or more
22 0.80 0.6 10.0 -- 1.4
3 months or more
23 1.20 2.0 5.0 -- 1.2
3 months or more
24 1.80 3.0 3.0 -- 1.1
3 months or more
25 0.44 2.0 5.0 1/9 1.6
3 months or more
26 0.24 2.0 5.0 1/1 1.8
3 months or more
27 0.05 2.0 5.0 9/1 1.9
3 months or more
__________________________________________________________________________
MO.sub.x : Conductive substance
Solids conc.: MO.sub.x + ZrO.sub.2 + SiO.sub.2
SiO.sub.2 /SiO.sub.2 : (SiO.sub.2 of nonsedimentary/(SiO.sub.2 of silicon
alkoxide) sillica)
The conductive coating liquids obtained respectively in Examples 20-27 were
individually coated on glass plates using a spinner at a rate of 2000 rpm,
and the glass plates thus coated were dried at 110.degree. C. and then
heated at 250.degree. C. to form their respective conductive coatings
thereon.
The coatings thus obtained were evaluated in the same manner as in Example
1. The results obtained are shown in Table 8. In the permanence property
test, the sample was immersed in an aqueous ammonia and in an aqueous
solution of NaCl, as in Example 1, and evaluated for total light
transmittance (t.sub.t) and adhesion of the coating to the glass plate.
TABLE 8
__________________________________________________________________________
Surface
Tt G H resistivity Permanence property test
Example
(%)
(%)
(%)
(.OMEGA./.quadrature.)
Adhesion
Hardness
Tt Adhesion
__________________________________________________________________________
20 91.5
150
1.5
8 .times. 10.sup.5
Accepted
>9H No change
Accepted
21 92.0
145
1.1
3 .times. 10.sup.6
Accepted
>9H No change
Accepted
22 91.0
156
1.6
2 .times. 10.sup.8
Accepted
>9H No change
Accepted
23 88.0
110
8.0
1 .times. 10.sup.7
Accepted
8H No change
Accepted
24 89.5
100
7.5
2 .times. 10.sup.4
Accepted
8H No change
Accepted
25 91.8
146
1.3
7 .times. 10.sup.5
Accepted
>9H No change
Accepted
26 92.5
140
1.1
5 .times. 10.sup.5
Accepted
>9H No change
Accepted
27 93.2
131
1.1
5 .times. 10.sup.5
Accepted
>9H No change
Accepted
__________________________________________________________________________
EXAMPLE 28
Preparation of partial hydrolysate of silicon alkoxide
Liquid H
To 100 g of ethyl silicate-28 was added with stirring 110 g of ethanol and
then added 70 g of an aqueous solution of 5% by weight of nitric acid. The
mixture was then heated at 60.degree. C. and kept at that temperature for
1 hour.
Liquid I
To 100 g of ethyl silicate-40 was added with stirring 200 g of ethanol and
then added 100 g of an aqueous solution of 1.0% by weight of acetic acid.
The mixture was then heated at 40.degree. C. and kept at that temperature
for 30 minutes.
Preparation of conductive substance
Liquid J
In 100 g of water was dispersed 20 g of the fine powder (I) obtained in
Example 1 and pulverized for 3 hours with a sand mill to obtain a
conductive tin oxide dispersion having an average particle diameter of 0.3
.mu.m.
Liquid K
The conductive sol obtained in Example 1 was used as liquid K.
Liquid L
In 100 g of water was dispersed 20 g of the fine powder (II) obtained in
Example 12 and pulverized for 3 hours with a sand mill to obtain a
conductive indium oxide having an average particle diameter of 0.3 .mu.m.
Subsequently, to 100 g of the liquid K obtained above was added 11.9 g of
ethanol and further added with stirring 3.1 g of 13% by weight of
dibutoxy-bisacetylacetonato zirconium (ABZ). To the mixture was added 70 g
of the liquid H and thoroughly dispersed to obtain a coating liquid for
forming conductive coating.
EXAMPLES 29-33 AND COMPARATIVE EXAMPLE 10
Substantially the same procedure as described in Example 28 was followed
except for a change in composition of the coating liquid used in each
example as shown in Table 9.
COMPARATIVE EXAMPLE 11
To a mixture comprising 100 g of the liquid K and 11.9 g of ethanol was
added with stirring 70 g of the liquid H. In the mixture was then
dispersed 3.1 g of 13% by weight of ABZ, whereupon aggregation of
colloidal particles took place several minutes after dispersing and the
aggregated particles precipitated.
COMPARATIVE EXAMPLE 12
To 35.7 g of ethyl silicate 28 was added with stirring 447.3 g of ethanol
followed by further addition of 4 g of ZON and 22 g of water. In the
mixture was thoroughly dispersed 100 g of the liquid K.
The coating liquids thus obtained were individually coated on substrates as
shown in Table 10 by the spinner or roll coater method to form their
respective coatings thereon.
Evaluation of the coatings thus formed was conducted in the same manner as
in Example 1.
In this connection, scratch resistance was measured in the following
manner.
That is, an eraser for office use (equivalent to No. 50--50, a product of
LION K.K.) was placed on the coating formed on PC (a polycarbonate plate)
or glass plate fixed onto a platform scale, and said coating was rubbed
300 times with the eraser under a load of 2 kg to measure total light
transmittance and surface resistivity.
The results obtained are shown in Table 10. In the test for alkali
resistance, the sample was immersed in 15% by weight aqueous ammonia at
room temperature for a week, and thereafter adhesion of the coating to the
substrate and surface resistivity of the coating were measured.
TABLE 9
__________________________________________________________________________
Average
Silicon
Solids
ZrO.sub.2
ZrO.sub.2
MO.sub.x
particle diam.
MO.sub.x Solvent AAZ alkoxide
concn.
MO.sub.x
SiO.sub.2
SiO.sub.2 + ZrO.sub.2
in coating
Pot life
(g) (g) (g) (g) (wt %)
(wt/wt)
(wt/wt)
(wt/wt)
(.mu.m) at 30.degree.
__________________________________________________________________________
C.
Example
28 liquid D
EtOH ABZ liquid H
14.8
0.02 0.057
2.7 0.07 >3 months
100 11.9 3.1 100
29 liquid D
EtOH ABZ liquid H
5.1 0.45 0.09 1.8 0.07 >6 months
100 402.9 6.9 100
30 liquid D
BuOH/MeOH
ABZ I 1.0 0.1 1.0 5.0 0.07 >6 months
100 2265 15.4
20
31 liquid D
EtOH/methy-
ABZ liquid H
8.0 1.0 1.0 0.5 0.07 >6 months
100 cello 153.8
200
296.2
32 liquid C
EtOH ABZ liquid H
5.1 0.45 0.09 1.8 0.3 >6 months
100 402.9 6.9 100
33 liquid E
EtOH ABZ liquid H
5.1 0.45 0.09 1.8 0.3 >6 months
100 402.9 6.9 100
Compar.
Example
10 liquid D
EtOH ABZ liquid H
5.0 1.5 3.0 0.5 0.07 >3 months
100 769.2 230.8
100
11 liquid D
EtOH ABZ liquid H
14.8
0.02 0.057
2.7 -- Aggregated
100 11.9 3.1 100
12 liquid D
EtOH 447.3
zirco
ES-28
5.1 0.05 0.1 1.8 0.16 7 days
100 H.sub.2 O 22
nitrate
35.7
4.0
__________________________________________________________________________
1. AAZ = Diacetylacetonatedialkoxy zirconium
2. ABZ = Diacetylacetonatedibutoxy zirconium
3. Methylcell = Methyl cellosolve
4. Zirco nitrate = Zirconium nitrate
5. ES28 = Ethyl silicate28
TABLE 10
__________________________________________________________________________
Scratch Alkali
Firing resistance
resistance
Coating temp.
Rs Tt H G Tt Rs Rs
process Substrate
(.degree.C.)
(.OMEGA./.quadrature.)
(%) (%) (%) Adhesion
(%)
(.OMEGA./.quadrature.)
Adhesion
(.OMEGA./.quadra
ture.)
__________________________________________________________________________
Example
28 Spinner
PC 150 2 .times. 10.sup.6
90.2 1.2 154 .smallcircle.
90.2
2 .times. 10.sup.6
.smallcircle.
2 .times.
10.sup.6
29 Roll coater
glass
150 1 .times. 10.sup.7
90.8 0.9 153 .smallcircle.
90.5
1 .times. 10.sup.7
.smallcircle.
1 .times.
10.sup.7
29 Roll coater
glass
200 5 .times. 10.sup.6
90.5 0.9 152 .smallcircle.
90.2
5 .times. 10.sup.6
.smallcircle.
5 .times.
10.sup.6
29 Roll coater
glass
450 5 .times. 10.sup.6
90.0 0.9 156 .smallcircle.
90.0
5 .times. 10.sup.6
.smallcircle.
5 .times.
10.sup.6
30 Roll coater
glass
250 3 .times. 10.sup.9
92.5 2.5 148 .smallcircle.
92.3
3 .times. 10.sup.9
.smallcircle.
3 .times.
10.sup.9
31 Roll coater
glass
400 5 .times. 10.sup.8
90.6 1.0 156 .smallcircle.
91.8
5 .times. 10.sup.8
.smallcircle.
5 .times.
10.sup.8
32 Roll coater
glass
200 5 .times. 10.sup.6
92.1 4.0 128 .smallcircle.
91.8
6 .times. 10.sup.6
.smallcircle.
5 .times.
10.sup.6
33 Roll coater
glass
200 3 .times. 10.sup.3
90.5 5.1 131 .smallcircle.
90.1
6 .times. 10.sup.3
.smallcircle.
3 .times.
30.sup.3
Compar.
Example
10 Roll coater
glass
200 .sup. 1 .times. 10.sup.12
Blushed
Blushed
Blushed
x -- -- -- --
12 Spinner
glass
150 8 .times. 10.sup.6
90.7 1.1 143 .smallcircle.
90.2
3 .times. 10.sup.8
x 2 .times.
10.sup.9
12 Spinner
glass
300 6 .times. 10.sup.6
90.4 1.3 147 .smallcircle.
90.1
6 .times. 10.sup.6
.smallcircle.
6 .times.
10.sup.6
12 Roll coater
glass
150 .sup. 1 .times. 10.sup.10
90.8 2.8 126 .smallcircle.
91.0
.sup. 1
xtimes. 10.sup.10
.sup. 1 .times.
10.sup.10
12 Roll coater
glass
300 5 .times. 10.sup.9
90.4 3.0 130 .smallcircle.
91.0
5 .times. 10.sup.9
.smallcircle.
5 .times.
10.sup.9
12 Roll coater
glass
450 1 .times. 10.sup.9
90.0 3.0 135 .smallcircle.
90.7
1 .times. 10.sup.9
.smallcircle.
1 .times.
10.sup.9
__________________________________________________________________________
PC = a polycarbonate plate, Glass = a glass plate, and the number of
rotation of the spinner is 2000 rpm RS = Surface resistivity.
EXAMPLE 34
A panel for 14-inch Braun tube kept at 60.degree. C. was spray coated under
a spray pressure of 3.0 kg/cm.sup.2 with 20 ml of the coating liquid for
forming conductive coating obtained in Example 13. Thereafter, the panel
thus coated was dried at 110.degree. C. and then heated at 450.degree. C.
for 30 minutes.
EXAMPLE 35
Example 34 was repeated except that the panel for 14-inch Braun tube was
kept at 70.degree. C.
EXAMPLE 36
Example 34 was repeated except that in place of the panel for 14-inch Braun
tube, an acrylic resin plate was used, and the plate was dried at
110.degree. C. for 30 minutes without subjecting it to subsequent heating.
EXAMPLE 37
A panel spray coated with the coating liquid for forming conductive coating
and dried at 110.degree. C. for 30 minutes in Example 34, was kept at
60.degree. C., and the panel was then spray coated under a spray pressure
of 3.0 kg/cm.sup.2 with 20 ml of a coating liquid containing transparent
protective components, which coating liquid has been obtained by
homogeneously mixing together 100 g of ethyl silicate 28 (a product of
Tama Kagaku K.K.), 749 g of isopropanol, 84 g of water and 0.5 g of 35% by
weight of hydrochloric acid. Thereafter, the panel thus coated was dried
at 110.degree. C. for 10 minutes and then heated at 450.degree. C. for 30
minutes.
EXAMPLE 38
A homogeneous mixture comprising 50 g of the non-sedimentary silica
dispersion obtained in Example 13 and 43 g of NMP was heated at 80.degree.
C. to distill off 93 g of water. The mixture obtained was cooled and mixed
with 120 g of ethanol to obtain a coating liquid containing transparent
protective components.
The panel obtained in Example 34 was kept at 60.degree. C. and spray coated
under a spray pressure of 3.0 kg/cm.sup.2 with 20 ml of the coating liquid
containing transparent protective components obtained above. Thereafter,
the panel thus coated was dried at 110.degree. C. for 10 minutes and then
heated at 250.degree. C. for 30 minutes.
EXAMPLE 39
A coating liquid containing transparent protective components was obtained
by mixing 10 g of 50% by weight of silicone resin (a xylene-diluted
product of Kanegafuchi Kagaku Industry Co., Ltd. under a trade name of
Cemlack) with 157 g of methyl ethyl ketone.
The panel obtained in Example 34 was kept at 60.degree. C. and spray coated
under a spray pressure of 3.0 kg/cm.sup.2 with 20 ml of the coating liquid
containing transparent protective components obtained above. Thereafter,
the panel thus coated was dried at 110.degree. C. for 10 minutes.
COMPARATIVE EXAMPLE 13
Example 34 was repeated except that the panel for 14-inch Braun tube was
kept at 110.degree. C.
COMPARATIVE EXAMPLE 14
Example 34 was repeated except that the coating liquid for forming
conductive coating obtained by thoroughly mixing together 100 g of the
non-sedimentary silica dispersion obtained in Example 13, 50 g of the
conductive sol obtained in Example 1, 25 g of NMP and 125 g of ethanol was
used. That is no oxysalt of zirconium was used.
COMPARATIVE EXAMPLE 15
With the purpose of preparing a coating liquid for forming conductive
coating, 100 g of the non-sedimentary silica dispersion obtained in
Example 13, 100 g of the conductive sol obtained in Example 1, 20 g of ZON
and 380 g of MeOH/EtOH (1/1 weight ratio) were thoroughly mixed together,
whereupon gellation occurred 30 minutes thereafter. (No stabilizer was
used.)
COMPARATIVE EXAMPLE 16
In the coating liquid for forming conductive coating obtained in Example 13
was immersed a glass plate (200.times.200.times.3 mm), and the plate was
then pulled up therefrom at a rate of 5 cm/min. Thereafter, the plate thus
treated was dried at 110.degree. C. for 30 minutes and then heated at
450.degree. C. for 30 minutes.
Evaluation of the foregoing examples and comparative examples was conducted
in the same manner as in Example 1.
The resolving power was measured by the method as described in the present
specification. Rz was measured in accordance with the method of
measurement of Rz stipulated in JIS B0601-82 using a Talystep sensor
(manufactured and sold by Rank Tyler Hobson Co.).
Evaluation of the coating film strength was conducted in the following
manner. That is, an eraser for office use (equivalent to No. 50--50, a
product of LION K. K.) was placed on the coating of the panel or acrylic
resin plate fixed onto a platform scale, and said coating was rubbed with
the eraser under a load of 2 kg distance until the surface of said panel
or acrylic resin plate is exposed, and the number of times of
reciprocating movements of the eraser required for was sought, on the
basis of which the coating film strength was determined.
In addition to the Example 1 of the test for permanence properties
described previously in the present specification, the test for permanence
properties conducted herein included 5) immersion of the plate in acetone
at room temperature for 1 week, 6) immersion of the plate in ethanol at
room temperature for 1 week, and 7) immersion of the plate in n-propanol
at room temperature for 1 week.
The results obtained are shown in Tables 11 and 12, respectively.
TABLE 11
__________________________________________________________________________
Film Average
Resolving
Gloss-
Surface strength
roughness
Item power iness
resistivity
Adhe-
(No. of
Rz
No. (Bar/cm)
G (%)
(.OMEGA./.quadrature.)
sion
times)
(.mu.m)
__________________________________________________________________________
Example
34 65 62 8 .times. 10.sup.6
.smallcircle.
100 0.95
35 65 63 7 .times. 10.sup.6
.smallcircle.
100 0.98
36 65 60 8 .times. 10.sup.7
.smallcircle.
50 1.10
37 70 54 9 .times. 10.sup.6
.smallcircle.
300 1.55
38 70 53 8 .times. 10.sup.6
.smallcircle.
200 1.63
39 65 57 2 .times. 10.sup.7
.smallcircle.
150 1.48
Compar.
Ex.
13 20 20 5 .times. 10.sup.6
x <25 6.20
14 65 60 5 .times. 10.sup.6
.smallcircle.
150 1.20
15 -- -- -- -- -- --
16 75 142 2 .times. 10.sup.6
.smallcircle.
250 0.10
__________________________________________________________________________
Notes: In Comparative Example 15, the coating liquid for forming
conductive coating gelled and no coating was formed.
TABLE 12
__________________________________________________________________________
Aqueous Boiling
Aqueous
ammonia
NaCl water
acetic acid
Acetone
Ethanol
n-Propanol
__________________________________________________________________________
Example
34
Glossiness (%)
60 61 62 60 61 61 61
Surface (.OMEGA./.quadrature.)
No change
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
.smallcircle.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
35
Glossiness (%)
60 62 63 61 62 61 62
Surface (.OMEGA./.quadrature.)
No change
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
.smallcircle.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
36
Glossiness (%)
57 59 58 56 59 59 59
Surface (.OMEGA./.quadrature.)
No change
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
.smallcircle.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
37
Glossiness (%)
53 54 54 53 54 54 54
Surface (.OMEGA./.quadrature.)
No change
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
.smallcircle.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
38
Glossiness (%)
51 52 50 54 53 53 53
Surface (.OMEGA./.quadrature.)
No change
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
.smallcircle.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
39
Glossiness (%)
55 56 55 57 57 57 57
Surface (.OMEGA./.quadrature.)
No change
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
.smallcircle.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
Compar.
Example
13
Glossiness (%)
Peeled off
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
Surface (.OMEGA./.quadrature.)
peeled off
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
peeled off
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
14
Glossiness (%)
Peeled off
170 85 60 60 60 60
Surface (.OMEGA./.quadrature.)
peeled off
9 .times. 10.sup.13
5 .times. 10.sup.8
No change
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
peeled off
x x .smallcircle.
.rarw.
.rarw.
.rarw.
16
Glossiness (%)
140 141 142 140 141 141 141
Surface (.OMEGA./.quadrature.)
No change
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
resistivity
Adhesion
.smallcircle.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
.rarw.
__________________________________________________________________________
COMMERCIAL POSSIBILITY OF THE INVENTION
Glass or plastic substrates provided with transparent conductive coatings
formed by the use of the coating liquid for forming conductive coatings of
the present invention are utilizable in the field of the articles of
manufacture where antistatic function and non-glare are required, such as
face-plates for display devices such as CRT or LCD, glass plates for copy
machines, panels for instruments, glass for clean rooms, transparent
digitizers, telewriting terminals and the like.
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